Fix FAB role deletion foreign key constraint violation

[kimjune01]

Summary

When deleting a FAB role via appbuilder.sm.delete_role(), the deletion fails with a foreign key constraint violation if the role has associated permissions or view menus. The delete operation attempts to remove the role record while the association table rows (ab_permission_view_role) still reference it.

This PR adds explicit cleanup of the many-to-many associations before deleting the role record itself. The fix mirrors the pattern already used in delete_user() within the same codebase.

Fixes #65375.

Test plan

• New unit test test_security_manager_delete_role_cleans_up_associations verifies that a role with permissions can be deleted without FK constraint errors
• Existing security manager tests still pass
• Manual verification: created a role with permissions, called delete_role(), confirmed clean deletion without errors

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Was generative AI tooling used to co-author this PR?

• Yes — Claude Opus 4.7 (1M context)

Generated-by: Claude Opus 4.7 (1M context) following the guidelines

[boring-cyborg]

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[boring-cyborg]

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