CodeEditor - testing is needed for interactions with React Dropzone and the Monaco Editor

As mentioned in #7450 the Code Editor is lacking in test coverage based on our newly determined testing guidelines.

I anticipate the most difficult part of this issue will likely be determining how we should test certain aspects surrounding the Monaco Editor and React Dropzone libraries that we use.

Monaco seems to do something that makes entering text in its editor difficult using RTL, and React Dropzone has functions (such as its open function) which I'm not sure how would be best to test.

Jira Issue: PF-182

まず Code Editor コンポーネントと #7450 のテストに関するガイダンスを確認し、次に React Testing Library が React Dropzone および Monaco Editor とどのように連携するかを調べます。どのインタラクションをカバレッジの対象にする必要があるかを判断し、作成したテストをプロジェクトのテストガイドラインに照らして確認します。