Shared channels auto-share DM & group messages (#26097)

* option for auto inviting plugin to all shared channels.
* auto-invite remotes to shared channels when flag set

server/platform/services/sharedchannel/sync_recv.go

@@ -317,7 +317,7 @@ func (scs *Service) updateSyncUser(rctx request.CTX, patch *model.UserPatch, use
 				)
 			}
 		} else {
-			scs.app.InvalidateCacheForUser(update.New.Id)
+			scs.platform.InvalidateCacheForUser(update.New.Id)
 			scs.app.NotifySharedChannelUserUpdate(update.New)
 			return update.New, nil
 		}