[PERF] Trace auth requests (#2589)

## Description of changes

*Summarize the changes made by this PR.*
 - Improvements & Bug fixes
- This traces calls to the auth system in the server so that we can
measure its latency in a span
 - New functionality
	 - None

## Test plan
*How are these changes tested?*
Manually verified in jaeger
![Screenshot 2024-07-29 at 1 02 06
PM](https://github.com/user-attachments/assets/262f9db8-6917-45f1-a026-1e72a34ad6e1)

- [ ] Tests pass locally with `pytest` for python, `yarn test` for js,
`cargo test` for rust

## Documentation Changes
*Are all docstrings for user-facing APIs updated if required? Do we need
to make documentation changes in the [docs
repository](https://github.com/chroma-core/docs)?*

chromadb/server/fastapi/__init__.py

@@ -350,6 +350,10 @@ async def heartbeat(self) -> Dict[str, int]:
     async def version(self) -> str:
         return self._api.get_version()
 
+    @trace_method(
+        "auth_and_get_tenant_and_database_for_request",
+        OpenTelemetryGranularity.OPERATION,
+    )
     def auth_and_get_tenant_and_database_for_request(
         self,
         headers: Headers,