rebase: bump google.golang.org/grpc from 1.67.1 to 1.68.0

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.67.1 to 1.68.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.67.1...v1.68.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Signed-off-by: Praveen M <m.praveen@ibm.com>

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

@@ -59,6 +59,8 @@ func NewServerMetricsForTesting(started, succeeded, failed, timestamp int64) *Se
 	return sm
 }
 
+// CopyFrom copies the metrics data from the provided ServerMetrics
+// instance into the current instance.
 func (sm *ServerMetrics) CopyFrom(o *ServerMetrics) {
 	sm.CallsStarted.Store(o.CallsStarted.Load())
 	sm.CallsSucceeded.Store(o.CallsSucceeded.Load())