Bump azure-identity from 1.17.1 to 1.19.0 in /app/api

Bumps [azure-identity](https://github.com/Azure/azure-sdk-for-python) from 1.17.1 to 1.19.0.
- [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_1.17.1...azure-identity_1.19.0)

---
updated-dependencies:
- dependency-name: azure-identity
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

app/api/requirements.txt

@@ -1,6 +1,6 @@
 fastapi[standard] == 0.112.0
 pydantic==2.8.2
-azure-identity==1.17.1
+azure-identity==1.19.0
 pydantic-settings==2.4.0
 azure-cosmos==4.7.0
 fastapi-azure-auth==5.0.0