Bump azure-identity from 1.15.0 to 1.16.1 in /samples/FileSearch/src

Bumps [azure-identity](https://github.com/Azure/azure-sdk-for-python) from 1.15.0 to 1.16.1.
- [Release notes](https://github.com/Azure/azure-sdk-for-python/releases)
- [Changelog](https://github.com/Azure/azure-sdk-for-python/blob/main/doc/esrp_release.md)
- [Commits](Azure/azure-sdk-for-python@azure-identity_1.15.0...azure-identity_1.16.1)

---
updated-dependencies:
- dependency-name: azure-identity
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

samples/FileSearch/src/requirements.txt

@@ -21,7 +21,7 @@ attrs==23.2.0
     # via aiohttp
 azure-core==1.30.1
     # via azure-identity
-azure-identity==1.15.0
+azure-identity==1.16.1
     # via quartapp (pyproject.toml)
 blinker==1.7.0
     # via