fix(milvus): Enhanced Milvus VectorDB Instrumentation for Improved search Monitoring

[divyapathak24]

Fixes #2808

• [x] I have added tests that cover my changes.
• [x] If adding a new instrumentation or changing an existing one, I've added screenshots from some observability platform showing the change.
• [x] PR name follows conventional commits format: feat(instrumentation): ... or fix(instrumentation): ....
• [ ] (If applicable) I have updated the documentation accordingly.

New search attributes for single-vector searches

New search attributes for multi-vector searches

Search Events to log results:

---

[!IMPORTANT] Enhance Milvus VectorDB instrumentation with detailed search monitoring attributes and events, and add tests for single and multi-vector searches.

• Instrumentation Enhancements:
  • Add search duration and result status attributes in _wrap() in wrapper.py.
  • Log search result events in _add_search_result_events() in wrapper.py.
  • Add new search attributes like MILVUS_SEARCH_RADIUS, MILVUS_SEARCH_METRIC_TYPE, and MILVUS_SEARCH_INDEX_TYPE in semconv_ai/__init__.py.
• Testing:
  • Add test_search.py to test single and multi-vector searches, verifying span attributes and events.
  • Test different radius values to ensure varying result counts.
• Misc:
  • Import time module in wrapper.py for measuring search duration.

^{This description was created by for 3fe4f70605773bf0e3a583b587db3d0982f384db. It will automatically update as commits are pushed.}