Unify MessageReceiver and MessageReceiverInner

ts/background.ts

@@ -2873,17 +2873,8 @@ export async function startApp(): Promise<void> {
     const details = ev.groupDetails;
     const { id } = details;
 
-    const idBuffer = id;
-    const idBytes = idBuffer.byteLength;
-    if (idBytes !== 16) {
-      window.log.error(
-        `onGroupReceived: Id was ${idBytes} bytes, expected 16 bytes. Dropping group.`
-      );
-      return;
-    }
-
     const conversation = await window.ConversationController.getOrCreateAndWait(
-      Bytes.toBinary(id),
+      id,
       'group'
     );
     if (isGroupV2(conversation.attributes)) {

ts/textsecure/messageReceiverEvents.ts

@@ -119,8 +119,13 @@ export class ContactSyncEvent extends Event {
   }
 }
 
+export type GroupEventData = Omit<ModifiedGroupDetails, 'id'> &
+  Readonly<{
+    id: string;
+  }>;
+
 export class GroupEvent extends Event {
-  constructor(public readonly groupDetails: ModifiedGroupDetails) {
+  constructor(public readonly groupDetails: GroupEventData) {
     super('group');
   }
 }