fix(setup): make step 39 repeatable (#9085)

# Which Problems Are Solved

When downgrading zitadel and upgrading it again, it might be that orgs
deleted in this period still have stale entries in the fields table.

# How the Problems Are Solved

- Make the cleanup repeatable
- Scope the query by instance so that an index is used.

cmd/setup/config.go

@@ -127,7 +127,6 @@ type Steps struct {
 	s37Apps7OIDConfigsBackChannelLogoutURI  *Apps7OIDConfigsBackChannelLogoutURI
 	s38BackChannelLogoutNotificationStart   *BackChannelLogoutNotificationStart
 	s40InitPushFunc                         *InitPushFunc
-	s39DeleteStaleOrgFields                 *DeleteStaleOrgFields
 }
 
 func MustNewSteps(v *viper.Viper) *Steps {