Make no start command test platform-aware for CF compatibility

[tnikolova82]

Make "no start command" test platform-aware for CF compatibility

What

Updates integration test to work on both Docker and CF platforms
Adds platform-specific assertions for error checking
Makes cleanup handler more robust for failed deployments

Why

The "there is no start command given" test was previously skipped on CF platform because it used Docker-specific commands (docker container logs). This prevented proper test coverage when running integration tests against Cloud Foundry environments.

Without this change:

• Test is skipped on CF platform, reducing test coverage
• No validation that apps without start commands fail properly on CF
• Integration test suite incomplete when run with SWITCHBLADE_PLATFORM=cf

How

Platform-specific test logic:

• Docker: Uses docker container logs to check for error message (existing behavior)
• CF: Checks deployment failure or uses cf logs --recent to validate error message

Improved cleanup:

• Added null check for app name before attempting deletion
• Removed strict expectation on cleanup success to handle failed deployments gracefully

Testing:

• Test now runs on both Docker and CF platforms
• Properly validates that apps without start commands fail with appropriate error messages
• Cleanup no longer fails when deployment didn't succeed

[ivanovac]

LGTM