Update dependency @ember/test-helpers to v3.3.1 (#547)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package.json

@@ -30,7 +30,7 @@
   "devDependencies": {
     "@ember/optional-features": "2.1.0",
     "@ember/string": "3.1.1",
-    "@ember/test-helpers": "3.3.0",
+    "@ember/test-helpers": "3.3.1",
     "@embroider/test-setup": "3.0.3",
     "@glimmer/component": "1.1.2",
     "@glimmer/tracking": "1.1.2",