Fix desktop sync with body-less messages.

libsignal/service/src/main/java/org/whispersystems/signalservice/api/messages/SignalServiceDataMessage.java

@@ -159,7 +159,21 @@ public class SignalServiceDataMessage {
 
   public boolean isGroupV2Update() {
     return isGroupV2Message() &&
-           !body.isPresent();
+           group.get().getGroupV2().get().hasSignedGroupChange() &&
+           !hasRenderableContent();
+  }
+
+  /** Contains some user data that affects the conversation */
+  public boolean hasRenderableContent() {
+    return attachments.isPresent()   ||
+           body.isPresent()          ||
+           quote.isPresent()         ||
+           contacts.isPresent()      ||
+           previews.isPresent()      ||
+           mentions.isPresent()      ||
+           sticker.isPresent()       ||
+           reaction.isPresent()      ||
+           remoteDelete.isPresent();
   }
 
   public int getExpiresInSeconds() {

libsignal/service/src/main/java/org/whispersystems/signalservice/api/messages/SignalServiceGroupV2.java

@@ -55,6 +55,10 @@ public final class SignalServiceGroupV2 {
     return signedGroupChange;
   }
 
+  public boolean hasSignedGroupChange() {
+    return signedGroupChange != null && signedGroupChange.length > 0;
+  }
+
   public static Builder newBuilder(GroupMasterKey masterKey) {
     return new Builder(masterKey);
   }