fix(test): add missing @testing-library/dom dev dependency

Author: Jmosier69

package-lock.json

@@ -32,6 +32,7 @@
     "publish": "emdash plugin publish --build"
   },
   "devDependencies": {
+    "@testing-library/dom": "^10.4.1",
     "@testing-library/jest-dom": "^6.4.0",
     "@testing-library/react": "^16.0.0",
     "@types/react": "^18.3.0",