Consider making the files button image margin an PF override

[jelly]

Explain what happens

Convert the overrides to PF5 overrides in Cockpit (at least the first one) and file PF issues (at least for the first one, where it should be more obvious and easy).

The override is here.

From: https://github.com/cockpit-project/cockpit-files/pull/670#pullrequestreview-2207264878

Version of Cockpit

No response

Where is the problem in Cockpit?

None

Server operating system

None

Server operating system version

No response

What browsers are you using?

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System log

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