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/subchannel.go

@@ -47,12 +47,14 @@ func (sc *SubChannel) id() int64 {
 	return sc.ID
 }
 
+// Sockets returns a copy of the sockets map associated with the SubChannel.
 func (sc *SubChannel) Sockets() map[int64]string {
 	db.mu.RLock()
 	defer db.mu.RUnlock()
 	return copyMap(sc.sockets)
 }
 
+// Trace returns a copy of the ChannelTrace associated with the SubChannel.
 func (sc *SubChannel) Trace() *ChannelTrace {
 	db.mu.RLock()
 	defer db.mu.RUnlock()