Add comprehensive e2e test coverage for AI Catalog flows
What does this MR do?
Adds comprehensive end-to-end (e2e) test coverage for Flows in the AI Catalog, mirroring the existing test suite for Agents.
Issue: #573010 (closed)
Test Coverage Added:
- Flow creation (ai_catalog_flow_create_spec.rb)
- Flow editing (ai_catalog_flow_update_spec.rb)
- Flow list view (ai_catalog_flows_list_spec.rb)
- Flow deletion (ai_catalog_flow_show_spec.rb)
These tests follow the same patterns and structure as the existing agent tests to ensure consistency.