fix(pgadmin): switch standalone pgAdmin to python3.12 site-packages path

[ValClarkson]

The new internal-registry pgAdmin image
(registry.internal.crunchydata.com/gitlab/crunchy-pgadmin4-ubi9@sha256: b10575053e71e820ae15747f5e11e543296f0dafeb5513bbf44a8053b5cd7c1a) ships pgadmin4 under /usr/local/lib/python3.12/site-packages/pgadmin4. The previous developers.crunchydata.com image was on python3.11, so the operator hard-codes that path. The startup script generated by the operator does cd "$PGADMIN_DIR", which fails on the new image with:

cd: /usr/local/lib/python3.11/site-packages/pgadmin4:
    No such file or directory

The container exits 1 immediately and the pod ends up in CrashLoopBackOff. This was caught running the
standalone-pgadmin-user-management kuttl suite against the new image.

• internal/controller/standalone_pgadmin/config.go: bump pgAdminDir from python3.11 -> python3.12 so the generated startup script's cd "$PGADMIN_DIR" succeeds.
• internal/controller/standalone_pgadmin/pod_test.go: refresh both golden pod-spec fixtures to match the new path.

Checklist:

• Have you added an explanation of what your changes do and why you'd like them to be included?
• Have you updated or added documentation for the change, as applicable?
• Have you tested your changes on all related environments with successful results, as applicable?
  • Have you added automated tests?

Type of Changes:

• New feature
• Bug fix
• Documentation
• Testing enhancement
• Other

What is the current behavior (link to any open issues here)?

What is the new behavior (if this is a feature change)?

• Breaking change (fix or feature that would cause existing functionality to change)

Other Information: