Align editor find widget with the notebook find widget

To allow more filters/scopes for the find widget in monaco editor (for example, supporting search in strings/comments), we may want to align the ux with the notebook find widget by moving Find in Selection icon into the Find Input

<img width="376" alt="image" src="https://user-images.githubusercontent.com/876920/157726354-b6906f8c-506b-497b-a876-a05795697cd8.png">
