Update dependency ember-test-selectors to v7

Author: renovate[bot]

ember/package.json

@@ -86,7 +86,7 @@
     "ember-source": "3.24.3",
     "ember-svg-jar": "2.3.3",
     "ember-template-lint": "2.21.0",
-    "ember-test-selectors": "5.0.0",
+    "ember-test-selectors": "7.1.0",
     "ember-truth-helpers": "3.0.0",
     "ember-web-app": "5.0.1",
     "eslint": "7.25.0",