Adds support for GMs in shared channels (#31403)

* Adds support for GMs in shared channels

* Fix linter

* Remove creatorID from slack call

---------

Co-authored-by: Miguel de la Cruz <miguel@ctrlz.es>

server/platform/services/sharedchannel/sync_recv.go

@@ -115,7 +115,7 @@ func (scs *Service) processSyncMessage(c request.CTX, syncMsg *model.SyncMsg, rc
 			continue
 		}
 
-		if targetChannel.Type != model.ChannelTypeDirect && team == nil {
+		if (targetChannel.Type != model.ChannelTypeDirect && targetChannel.Type != model.ChannelTypeGroup) && team == nil {
 			var err2 error
 			team, err2 = scs.server.GetStore().Channel().GetTeamForChannel(syncMsg.ChannelId)
 			if err2 != nil {