[fix](fe) Cascade revoke privileges when dropping resources

[heguanhui]

What problem does this PR solve?

Issue Number: close #xxx

Problem Summary: When a resource (database, table, resource, workload group, or catalog) is dropped, the corresponding privilege entries in roles are not cleaned up. This causes SHOW GRANTS to display orphan privileges that reference non-existent resources. These orphan entries persist across FE restarts because the original GRANT records are replayed from BDB edit logs without any corresponding cleanup.

Release note

Fix orphan privilege entries displayed by SHOW GRANTS after dropping databases, tables, resources, workload groups, or catalogs. Privileges referencing dropped resources are now cascade-revoked automatically.

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes. Dropping a database/table/resource/workload group/catalog now cascade-revokes all privilege entries referencing that resource across all roles.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label

[hello-stephen]

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