AI Catalog: Add ability to search flows

What does this MR do and why?

AI Catalog: Add ability to search flows

Behind :global_ai_catalog and :ai_catalog_flows feature flags

References

Screenshots or screen recordings

Screen_Recording_2025-10-16_at_1.25.31_pm

How to set up and validate locally

1. Enable the Feature Flags:

   Feature.enable(:global_ai_catalog)
   Feature.enable(:ai_catalog_flows)

2. Visit http://gdk.test:3000/explore/ai-catalog/flows

3. Search flows

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #577435