Fix predefined prompts for narrow viewports

What does this MR do and why?

Fix predefined prompts for narrow viewports

:Behind FF gitlab_duo

Screenshots or screen recordings

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Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

Make sure Gitlab Duo is working on your local setup by following these steps

1. Open the Gitlab Duo chat in the group where you enabled the Ultimate license in the above setup process
2. Click on Help in the left navbar and then click on Ask Gitlab Duo
3. Check the predefined prompts in small screens , they should not overflow
4. Check for any screen size and the prompts should not break

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.

Related to #416235