[BUG] Fix as_nanos bad merge (chroma-core#1928)

## Description of changes

*Summarize the changes made by this PR.*
 - Improvements & Bug fixes
	 - chroma-core#1927 accidentally reverted chroma-core#1918 
 - 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

## Documentation Changes
none

rust/worker/src/execution/orchestration/hnsw.rs

@@ -123,7 +123,7 @@ impl HnswQueryOrchestrator {
         let end_timestamp = SystemTime::now().duration_since(UNIX_EPOCH);
         let end_timestamp = match end_timestamp {
             // TODO: change protobuf definition to use u64 instead of i64
-            Ok(end_timestamp) => end_timestamp.as_secs() as i64,
+            Ok(end_timestamp) => end_timestamp.as_nanos() as i64,
             Err(e) => {
                 // Log an error and reply + return
                 return;