Use instagram.com suffix for backfilled event IDs (#79)

mautrix_instagram/portal.py

@@ -1611,7 +1611,7 @@ class Portal(DBPortal, BasePortal):
             hash_content += f"/{part_name}"
         hashed = hashlib.sha256(hash_content.encode("utf-8")).digest()
         b64hash = base64.urlsafe_b64encode(hashed).decode("utf-8").rstrip("=")
-        return EventID(f"${b64hash}:telegram.org")
+        return EventID(f"${b64hash}:instagram.com")
 
     async def handle_instagram_remove(self, item_id: str) -> None:
         message = await DBMessage.get_by_item_id(item_id, self.receiver)