Add cancel button for "Offload files"

[grishy]

trafficstars

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• [X] I have read CONTRIBUTING.md
• [X] I have searched the existing requests and didn't find any that were similar
• [X] I have considered creating a pull request instead and want to proceed

Clear and concise description of the problem

When you click on "Offload files" in Data management, after that you can click only on "Yes", no option to cancel it except Esc btn.

Suggested solution

It would be convenient to opt-out not only using Esc Add a button to close or cross in the corner.

Alternative

No response

Additional context

Version - 0.42.4