- Fix (regression): Extension locale loading for non-English locales

- Fix: Allow language to be properly set back to a different locale and
  retaining preference (and ensure language changes are available before
  dialog closed)
- Refactoring: array extra/spread operator
- npm: Update devDep (sinon-test)

package.json

@@ -90,7 +90,7 @@
     "rollup-plugin-re": "^1.0.7",
     "rollup-plugin-terser": "^3.0.0",
     "sinon": "^7.0.0",
-    "sinon-test": "^2.3.0",
+    "sinon-test": "^2.4.0",
     "testcafe": "^0.22.0"
   }
 }