do not fail on @ember/string deprecation in Ember 4.12

Author: Gaurav0

config/ember-try.js

@@ -43,6 +43,9 @@ module.exports = async function () {
             bootstrap: bootstrapVersion,
           },
         },
+        env: {
+          FAIL_ON_DEPRECATION: false,
+        },
       },
       {
         name: 'ember-release',