[CHORE] Add some debug to hnsw index load (#5979)

## Description of changes

_Summarize the changes made by this PR._

- Improvements & Bug fixes
  - Add some better tracing
- New functionality
  - None

## Test plan

_How are these changes tested?_
- [x] Tests pass locally with `pytest` for python, `yarn test` for js,
`cargo test` for rust

## Migration plan
None

## Observability plan
None

## Documentation Changes
None

Author: HammadB

rust/index/src/hnsw_provider.rs

@@ -342,8 +342,7 @@ impl HnswIndexProvider {
             .map(|s| Self::format_key(prefix_path, source_id, s))
             .collect();
         let key_refs: Vec<&str> = keys.iter().map(|s| s.as_str()).collect();
-        let s3_fetch_span =
-            tracing::trace_span!(parent: Span::current(), "Read hnsw files from s3 into index");
+        let s3_fetch_span = tracing::trace_span!(parent: Span::current(), "Read hnsw files from s3 into index", index_id = %source_id, prefix_path = %prefix_path);
         let result = self
             .storage
             .fetch_batch(