Find & Replace is not fully functional for keyboard users.

Bug Description:

In both Theia and VS Code pressing enter in the focused input(where the new value is entered in find and replace) does not replace the contents I have to manually click on the small icon next to the input. I was expecting it to work when the enter key is pressed.

To me, it looks like a serious accessibility issue for Keyboard users and generally, it would be great if the whole Theia IDE is accessible for those users who only use a keyboard and can't use a mouse.

Steps to Reproduce:

1. Open a Gitpod workspace.
2. Try to find and replace some text via the Keyboard.

Additional Information

• Operating System:
• Theia Version: