assistant: Allow accepting terminal inline assist suggestion without executing command (#17299)

This adds a new button that on click, accepts the suggestion but does
not run the generated command.


https://github.com/user-attachments/assets/426b0ff3-8e19-435a-aa7f-89e062aefd4c

@danilo-leal @iamnbutler Any ideas on how to make both options
discoverable without having an extra button?

Release Notes:

- Added a way to accept terminal inline assist suggestions without
executing them

---------

Co-authored-by: Danilo Leal <67129314+danilo-leal@users.noreply.github.com>

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