rebase: bump google.golang.org/grpc from 1.72.2 to 1.73.0

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.72.2 to 1.73.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.72.2...v1.73.0)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-version: 1.73.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

vendor/google.golang.org/grpc/internal/internal.go

@@ -266,6 +266,13 @@ var (
 	TimeAfterFunc = func(d time.Duration, f func()) Timer {
 		return time.AfterFunc(d, f)
 	}
+
+	// NewStreamWaitingForResolver is a test hook that is triggered when a
+	// new stream blocks while waiting for name resolution. This can be
+	// used in tests to synchronize resolver updates and avoid race conditions.
+	// When set, the function will be called before the stream enters
+	// the blocking state.
+	NewStreamWaitingForResolver = func() {}
 )
 
 // HealthChecker defines the signature of the client-side LB channel health