Remove hover/focus states in accordion controls

[joedolson]

Removes some hover/focus states that use old color scheme, and are largely overridden by new schemes without change.

Trac ticket: https://core.trac.wordpress.org/ticket/64731

Use of AI Tools

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[joedolson]

On the whole, there are a lot of old colors in the customizer, and I think many could be removed. Not going to tackle that at this time of night, however...

[github-actions]

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