feat: add error handling for application/problem+json responses

[displague]

While the Equinix Metal API does not return this API header natively, tools such as Spotlight Prism can proxy the API and they may return this standard error content-type.

https://datatracker.ietf.org/doc/html/rfc7807

How has this been tested?

As demonstrated in https://gist.github.com/displague/27363182851f0eab4b599401f83f4b1e, errors returned with this content type are passed through as a JSON blob.

{"type":"https://stoplight.io/prism/errors#VIOLATIONS","title":"Request/Response not valid","status":500,"detail":"Your request/response is not valid and the --errors flag is set, so Prism is generating this error for you.","validation":[{"location":["response","body","plans","0","type"],"severity":"Error","code":"type","message":"Request body property plans.0.type must be string"},{"location":["response","body","plans","0","type"],"severity":"Error","code":"enum","message":"Request body property plans.0.type must be equal to one of the allowed values: standard, workload_optimized, custom"},{"location":["response","body","plans","1","specs","drives","1","type"],"severity":"Error","code":"enum","message":"Request body property plans.1.specs.drives.1.type must be equal to one of the allowed values: HDD, SSD, NVME"},{"location":["response","body","plans","1","type"],"severity":"Error","code":"type","message":"Request body property plans.1.type must be string"},{"location":["response","body","plans","1","type"],"severity":"Error","code":"enum","message":"Request body property plans.1.type must be equal to one of the allowed values: standard, workload_optimized, custom"},{"location":["response","body","plans","2","specs","drives","1","type"],"severity":"Error","code":"enum","message":"Request body property plans.2.specs.drives.1.type must be equal to one of the allowed values: HDD, SSD, NVME"},{"location":["response","body","plans","11","specs","drives","1","type"],"severity":"Error","code":"enum","message":"Request body property plans.11.specs.drives.1.type must be equal to one of the allowed values: HDD, SSD, NVME"},{"location":["response","body","plans","23","type"],"severity":"Error","code":"type","message":"Request body property plans.23.type must be string"},{"location":["response","body","plans","23","type"],"severity":"Error","code":"enum","message":"Request body property plans.23.type must be equal to one of the allowed values: standard, workload_optimized, custom"},{"location":["response","body","plans","24","type"],"severity":"Error","code":"type","message":"Request body property plans.24.type must be string"},{"location":["response","body","plans","24","type"],"severity":"Error","code":"enum","message":"Request body property plans.24.type must be equal to one of the allowed values: standard, workload_optimized, custom"},{"location":["response","body","plans","25","type"],"severity":"Error","code":"type","message":"Request body property plans.25.type must be string"},{"location":["response","body","plans","25","type"],"severity":"Error","code":"enum","message":"Request body property plans.25.type must be equal to one of the allowed values: standard, workload_optimized, custom"},{"location":["response","body","plans","26","type"],"severity":"Error","code":"type","message":"Request body property plans.26.type must be string"},{"location":["response","body","plans","26","type"],"severity":"Error","code":"enum","message":"Request body property plans.26.type must be equal to one of the allowed values: standard, workload_optimized, custom"},{"location":["response","body","plans","28","specs","drives","0","type"],"severity":"Error","code":"enum","message":"Request body property plans.28.specs.drives.0.type must be equal to one of the allowed values: HDD, SSD, NVME"},{"location":["response","body","plans","28","specs","nics","0","type"],"severity":"Error","code":"enum","message":"Request body property plans.28.specs.nics.0.type must be equal to one of the allowed values: 1Gbps, 10Gbps, 25Gbps"},{"location":["response","body","plans","29","specs","drives","0","type"],"severity":"Error","code":"enum","message":"Request body property plans.29.specs.drives.0.type must be equal to one of the allowed values: HDD, SSD, NVME"},{"location":["response","body","plans","29","specs","nics","0","type"],"severity":"Error","code":"enum","message":"Request body property plans.29.specs.nics.0.type must be equal to one of the allowed values: 1Gbps, 10Gbps, 25Gbps"},{"location":["response","body","plans","42","type"],"severity":"Error","code":"type","message":"Request body property plans.42.type must be string"},{"location":["response","body","plans","42","type"],"severity":"Error","code":"enum","message":"Request body property plans.42.type must be equal to one of the allowed values: standard, workload_optimized, custom"},{"location":["response","body","plans","43","specs","drives","1","type"],"severity":"Error","code":"enum","message":"Request body property plans.43.specs.drives.1.type must be equal to one of the allowed values: HDD, SSD, NVME"},{"location":["response","body","plans","43","type"],"severity":"Error","code":"type","message":"Request body property plans.43.type must be string"},{"location":["response","body","plans","43","type"],"severity":"Error","code":"enum","message":"Request body property plans.43.type must be equal to one of the allowed values: standard, workload_optimized, custom"},{"location":["response","body","plans","44","specs","drives","1","type"],"severity":"Error","code":"enum","message":"Request body property plans.44.specs.drives.1.type must be equal to one of the allowed values: HDD, SSD, NVME"}]}