Update AnVIL CMG auth config to use External Credentials Manager endpoint

[NoopDog]

Summary

Update the nihStatus endpoint URL in AnVIL CMG site configs to point to the External Credentials Manager (ECM) service, replacing the Firecloud Orchestration endpoint.

Background

Depends on DataBiosphere/findable-ui#819 migrating the response handling first.

Changes required

1. site-config/anvil-cmg/prod/authentication/constants.ts

• Change nihStatus from:
  https://firecloud-orchestration.dsde-prod.broadinstitute.org/api/nih/status
  to:
  https://externalcreds.dsde-prod.broadinstitute.org/api/oauth/v1/{provider}

2. site-config/anvil-cmg/dev/authentication/constants.ts

• Change to the corresponding dev ECM URL:
  https://externalcreds.dsde-dev.broadinstitute.org/api/oauth/v1/{provider}

3. site-config/anvil-cmg/tempdev/authentication/constants.ts

• Update to match prod or dev as appropriate

Open question

The ECM provider path parameter accepts: ras, era-commons, github, fence, dcf-fence, kids-first, anvil, sage. Need to confirm whether ras or era-commons is the correct provider for this use case.

Dependency

This ticket depends on DataBiosphere/findable-ui#819 being completed first, since the new endpoint returns a different response shape.