cert-manager-app release v3.9.4

Changed

• Upgrade cert-manager to v1.18.2.

Added

• Add E2E tests using apptest-framework for automated PR testing across multiple providers (CAPA, CAPV, CAPZ, CAPVCD).
  • Basic test suite: Validates fresh installations
  • Upgrade test suite: Tests upgrade scenarios and certificate reconciliation
• Add certificate issuance integration test to cluster-test-suites.