Prevent IMEs from triggering when editing a readonly code editor

[AndrewBastin]

This small patch introduces a small update that blocks IMEs from starting composition when editing a readonly code editor instance.

This is especially useful on mobile devices where the virtual keyboard is triggered when the REST Response Body is tapped on which further reduces the screen space.

Checks

• My pull request adheres to the code style of this project
• My code requires changes to the documentation
• I have updated the documentation as required
• All the tests have passed

Additional Information

Check IME behavior on Android and iOS and see how they react on readonly and readwrite fields.