[REF] web: remove unused legacy fn from action service

This function became useless at some point, after the views and
actions have been all converted to owl.

closes odoo/odoo#133699

Signed-off-by: Pierre Rousseau (pro) <pro@odoo.com>

addons/web/static/src/webclient/actions/action_service.js

@@ -1459,9 +1459,6 @@ function makeActionManager(env) {
         get currentController() {
             return _getCurrentController();
         },
-        __legacy__isActionInStack(actionId) {
-            return controllerStack.find((c) => c.action.jsId === actionId);
-        },
     };
 }