test: cover OIDC upstream allowPrivateIPs in BuildAuthServerRunConfig

[alex-feel]

#6428 delivered what this PR originally added: allowPrivateIPs on OIDCUpstreamConfig, wired through buildOIDCUpstreamRunConfig. After a rebase onto current main, the field and all generated manifests are upstream's own, so this PR is now scoped to the piece #6428 did not include: direct regression coverage of the OIDC-side mapping.

What it adds:

• a default-false assertion on the existing OIDC-upstream case in TestBuildAuthServerRunConfig;
• an end-to-end case exercising both OIDCUpstreamConfig.AllowPrivateIPs and OAuth2UpstreamConfig.AllowPrivateIPs reaching their run configs through BuildAuthServerRunConfig.

This closes the coverage half of the #4523 ask; the capability itself shipped in v0.46.0.

[alex-feel]

Updated the branch. Since #6320 added allowPrivateIPs to OAuth2UpstreamConfig (for RFC 8693 delegate clients), this PR no longer needs to add anything on the OAuth2 side. The change is now scoped to the OIDC side only: allowPrivateIP on OIDCUpstreamConfig, mapped in buildOIDCUpstreamRunConfig, with the CRD manifests regenerated accordingly; buildOAuth2UpstreamRunConfig simply uses the pre-existing field. TestBuildAuthServerRunConfig still covers both provider types — the new allowPrivateIP field on the OIDC config and the pre-existing allowPrivateIPs field on the OAuth2 config both reaching the run config. The PR description has been updated to match.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.06%. Comparing base (0fb54d4) to head (32f6cda).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6288      +/-   ##
==========================================
+ Coverage   78.01%   78.06%   +0.04%     
==========================================
  Files         767      767              
  Lines       74273    74273              
==========================================
+ Hits        57947    57981      +34     
+ Misses      16321    16287      -34     
  Partials        5        5              

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[jhrozek]

huh for some reason CI doesn't kick in?

[alex-feel]

Rebased onto current main. #6428 added the CRD field and its wiring while this PR was open, so the remaining diff is the OIDC-side regression coverage #6428 did not include. Retitled and re-described to match.