fix: storage controller registration script

[rahulinux]

Cplane only accept node_id as integer and script were sending string.

neon-control-plane-api-0 neon-control-plane {"level":"ERR","ts":"2024-03-04T12:51:53.388Z","logger":"managementapiv2","message":"incoming request finished with error","http_meth":"POST","http_path":"/management/api/v2/pageservers","route":"PageserverRegister","request_id":"8c1da1d9ae780811e3debd558cc261b6","trace_id":"2qCK96h5WSEyyNMa4CB9Qc","ingress_duration_ms":0,"status":400,"error":"invalid request: decode application/json: decode PageserverRegisterRequest: callback: decode field \"node_id\": unexpected byte 34 '\"' at 495: operation PageserverRegister: decode request: decode application/json: decode PageserverRegisterRequest: callback: decode field \"node_id\": unexpected byte 34 '\"' at 495","errorVerbose":"invalid request: decode application/json: decode PageserverRegisterRequest: callback: decode field \"node_id\": unexpected byte 34 '\"' at 495:\n    github.com/neondatabase/cloud/internal/semerr.errFmt\n        /build/internal/semerr/semantic.go:65\n  - operation PageserverRegister: decode request:\n      - decode application/json:\n        body: {\"host\": \"storage-controller.beta.us-east-2.internal.aws.neon.build\", \"region_id\": \"aws-us-east-2\", \"port\": 6400, \"disk_size\": 0, \"instance_id\": \"storage-controller.beta.us-east-2.internal.aws.neon.build\", \"http_host\": \"storage-controller.beta.us-east-2.internal.aws.neon.build\", \"http_port\": 50051, \"availability_zone_id\": \"us-east-2c\", \"instance_type\": \"\", \"register_reason\": \"Storage Controller Virtual Pageserver\", \"active\": false, \"is_storage_controller\": true, \"version\": 4767, \"node_id\": \"9315\"}\n