[ui] Squashing Ember deprecations (#22424)

* Now that message is a gettable on the task-event model, no longer needs to be attrs-set at serializer

* xstate future-proofing default prop

ui/app/machines/evaluations.js

@@ -8,6 +8,7 @@ import { assign, createMachine, send } from 'xstate';
 // Docs on using statecharts:  https://xstate.js.org/docs/packages/xstate-fsm/#api
 export default createMachine(
   {
+    predictableActionArguments: true,
     id: 'evaluations_ui',
     context: { evaluation: null },
     type: 'parallel',

ui/app/serializers/task-event.js

@@ -8,9 +8,5 @@ import classic from 'ember-classic-decorator';
 
 @classic
 export default class TaskEventSerializer extends ApplicationSerializer {
-  attrs = {
-    message: 'DisplayMessage',
-  };
-
   separateNanos = ['Time'];
 }