Update health check to use default implementation

[dmanc]

Why are these changes needed?

Use default health check implementation https://pkg.go.dev/google.golang.org/grpc/health

Tested with https://github.com/grpc-ecosystem/grpc-health-probe

grpc-health-probe -tls -addr=disperser.eigenda-preprod.eigenops.xyz:443 -service="disperser.Disperser" 
status: SERVING

grpc-health-probe -tls -addr=disperser.eigenda-preprod.eigenops.xyz:443 -service="aaa"       
error: health rpc failed: rpc error: code = NotFound desc = unknown service

grpc-health-probe -tls -addr=disperser.eigenda-preprod.eigenops.xyz:443 -service="disperser.Disperser"
error: health rpc failed: rpc error: code = Unavailable desc = unexpected HTTP status code received from server: 503 (Service Unavailable)

Checks

• I've made sure the lint is passing in this PR.
• I've made sure the tests are passing. Note that there might be a few flaky tests, in that case, please comment that they are not relevant.
• Testing Strategy
  • Unit tests
  • Integration tests
  • This PR is not tested :(

[jianoaix]

LG!