Give users option to override Claro --font-size-xs with --font-size-s

Not sure what the MR is doing but doesn't match the proposed solution. Putting back to active because of that.

The proposed solution says

Add a preference for minimum size to the user page /user/[userNumber]/edit

But for which all text should that font size be applied? Is it like, if there are texts with font size below the specified font size in the user page, then those text should use the font size given in the user page?
Another apporoach I would propose is to create a checkbox in user page enabling which will use --font-size-s in places where --font-size-xs and --font-size-xxs are currently used.

Actually it could be a drop-down for minimum font size:

Extra Extra Small (default)
Extra Small
Small
Unreduced

I just tried a mock up of how the form field will look like in the user profile.

This require more work as it will change all the font size of admin ui text based on the value selected in user profile.

@nayana_mvr That mock-up is exactly what I have in mind, thank you. I would be likely to use the Unreduced setting.

I'll note "Suggest the minimum font size for Admin UI." might be too small for some people to read if they haven't set it. Although I realize they can use browser zoom to read it, make the setting, then reset browser zoom to actual size once they've set it.