[BUG] Log service N+1 query (#1923)

## Description of changes

*Summarize the changes made by this PR.*
 - Improvements & Bug fixes
- The rust log service makes an additional query when it doesn't need to
if the timestamp is provided and we read less than a batch size. This
means that we are done reading the log and don't need to fetch again.
 - 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/operators/pull_log.rs

@@ -123,6 +123,13 @@ impl Operator<PullLogsInput, PullLogsOutput> for PullLogsOperator {
             offset += batch_size as i64;
             result.append(&mut logs);
 
+            // We used a a timestamp and we didn't get a full batch, so we have retrieved
+            // the last batch of logs relevant to our query
+            if input.end_timestamp.is_some() && num_records_read < batch_size as usize {
+                break;
+            }
+
+            // We have read all the records up to the size we wanted
             if input.num_records.is_some()
                 && num_records_read >= input.num_records.unwrap() as usize
             {