[chore] update otel libraries (#3740)

* chore: update otel dependencies

* refactor: combine tracing & metrics in observability package

* chore: update example tracing compose file

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()