* fix: Use get_index() instead of list_indexes() in has_collection() to handle pagination
Fixes#19233
Replace list_indexes() pagination scan with direct get_index() lookup
in has_collection() method. The previous implementation only checked
the first ~1,000 indexes due to unhandled pagination, causing RAG
queries to fail for indexes beyond the first page.
Benefits:
- Handles buckets with any number of indexes (no pagination needed)
- ~8x faster (0.19s vs 1.53s in testing)
- Proper exception handling for ResourceNotFoundException
- Scales to millions of indexes
* Update s3vector.py
Unneeded exception handling removed to match original OWUI code