task(many): Fix YN0068

Because:
- We are cleaning up yarn warnings.
- We want to address YN0068 errors

This Commit:
- Removes `react-document-title@*:` from the packageExtensions defined in `.yarnrc.yml`
- It appears this extension was no longer needed / referenced.

.yarnrc.yml

@@ -8,9 +8,6 @@ packageExtensions:
   fxa-pairing-channel@*:
     dependencies:
       webpack: ^4.43.0
-  react-document-title@*:
-    dependencies:
-      react: ^16.13.1
 
 plugins:
   - path: .yarn/plugins/@yarnpkg/plugin-typescript.cjs