[Bug report] Align group detail authorization behavior

[roryqi]

Version

main branch

Describe what's wrong

Group detail loading should follow the same authorization metadata path as related access-control APIs.

Error message and/or stacktrace

N/A

How to reproduce

Review the group detail loading REST operation and compare its authorization metadata with related user/group operations.

Additional context

This is addressed by aligning the group load authorization expression and adding focused regression coverage.