chore: bump azure-identity from 1.14.0 to 1.15.0

Bumps [azure-identity](https://github.com/Azure/azure-sdk-for-python) from 1.14.0 to 1.15.0.
- [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_1.14.0...azure-identity_1.15.0)

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

Signed-off-by: dependabot[bot] <support@github.com>