server: the /_status/nodes endpoint fails with code 501 even with 'can-view-node-info' capability

[knz]

Found while investigating #110001.

Describe the problem

When TestSSLEnforcement in server/authserver is modified to point to a secondary tenant (e.g. via #110008), the test starts failing when accessing the /_status/nodes endpoint:

=== RUN   TestSSLEnforcement//_status/nodes
    authentication_test.go:205: expected status code 200, got 501
    authentication_test.go:207: orig=/_status/nodes url=<nil> err=http: no Location header in response
=== RUN   TestSSLEnforcement//_status/nodes#01
    authentication_test.go:205: expected status code 200, got 501
    authentication_test.go:207: orig=/_status/nodes url=<nil> err=http: no Location header in response
=== RUN   TestSSLEnforcement//_status/nodes#02
    authentication_test.go:205: expected status code 200, got 501
    authentication_test.go:207: orig=/_status/nodes url=<nil> err=http: no Location header in response
=== RUN   TestSSLEnforcement//_status/nodes#03
    authentication_test.go:205: expected status code 200, got 501
    authentication_test.go:207: orig=/_status/nodes url=<nil> err=http: no Location header in response

Expected behavior

Once the tenant is granted can_view_node_info, the endpoint should work properly.

Epic CRDB-38968

Jira issue: CRDB-31215