Fix wrong avatars when inviting multiple users when creating room

We reused the `content` dictionary between invite requests, which meant they could end up reusing the profile info for a previous user

synapse/handlers/room.py

@@ -205,12 +205,12 @@ class RoomCreationHandler(BaseHandler):
                 },
                 ratelimit=False)
 
-        content = {}
-        is_direct = config.get("is_direct", None)
-        if is_direct:
-            content["is_direct"] = is_direct
-
         for invitee in invite_list:
+            content = {}
+            is_direct = config.get("is_direct", None)
+            if is_direct:
+                content["is_direct"] = is_direct
+            
             yield room_member_handler.update_membership(
                 requester,
                 UserID.from_string(invitee),