PR #103526 - jwtauthccl: allow cluster SSO to pick principals from custom claims

[cockroach-teamcity]

Exalate commented:

Related PR: https://github.com/cockroachdb/cockroach/pull/103526 Commit: https://github.com/cockroachdb/cockroach/commit/ed538d0d393730f82d957c239c13e805f8a2af1e Fixes: CC-24595

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Release note (enterprise change): Cluster SSO (JWT authentication) can now read SQL usernames from any JWT claims instead of requiring the subject claim to be used. The claim can be controlled by the server.jwt_authentication.claim cluster setting with an empty string or "sub" being equivalent to the previous behavior.

Jira Issue: DOC-7697