fix: propagate role removal to postgres cluster when databases are removed from postgres database spec

[mploski]

Description

Fixes a bug where removing a database from postgres database CR spec.databases (or deleting the CR with DeletionPolicy: Delete) did not cause the corresponding PostgreSQL roles to be dropped in postgres cluster. postgres cluster only drops a role from cnpg when it receives Exists: false in the cluster spec — previously, removed roles were never marked absent but silently wiped out

Key Changes

• api/v4/postgrescluster_types.go — removed omitempty from ManagedRole.Exists
• pkg/postgresql/database/core/database.go:
  • cleanupManagedRoles now sends retained + deleted roles together in one SSA patch
• internal/controller/postgresdatabase_controller_test.go — added integration test for DB removal while CR stays alive;
  extracted expectManagedRoleExists helper used across both role lifecycle tests

Testing and Verification

Added unit and integration tests. All green

Related Issues

Jira tickets, GitHub issues, Support tickets...

PR Checklist

• Code changes adhere to the project's coding standards.
• Relevant unit and integration tests are included.
• Documentation has been updated accordingly.
• All tests pass locally.
• The PR description follows the project's guidelines.

[github-actions]

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