[FIX] rma: Change code to get the correct rmas (move_ids.rma_ids)

rma/models/stock_picking.py

@@ -30,8 +30,8 @@ class StockPicking(models.Model):
 
     def action_view_rma(self):
         self.ensure_one()
-        action = self.sudo().env.ref("rma.rma_action").read()[0]
-        rma = self.move_ids.mapped("rma_ids")
+        action = self.env["ir.actions.act_window"]._for_xml_id("rma.rma_action")
+        rma = self.move_ids.rma_ids
         if len(rma) == 1:
             action.update(
                 res_id=rma.id,