[RBAC] Generate unique cephx IDs for each operation in tests

The current tests encounter issues due to the reuse of the same
cephx ID for multiple operations. This can lead to conflicts and
test failures.
This patch resolves the issue by ensuring that each operation
generates and uses a unique cephx ID, preventing conflicts and
improving test reliability.

Closes-Bug: #2071433
Change-Id: I837907e3472acc4580727b05c47c70c2e0767e93
1 file changed