Update comments

Author: qdpham13

firebase-config/src/main/java/com/google/firebase/remoteconfig/internal/ConfigRealtimeHttpClient.java

@@ -18,7 +18,7 @@ public ConfigRealtimeHttpClient() {
         listenerCount = 1;
     }
 
-    // Kicks off Http stream listening and autofetch
+    // Kicks off Http stream listening and autofetch. Will implement in later PRs
     private void beginRealtimeStream() {
     }