Removes [data-focused] styling for Selector

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Fixes #35, #39

• As documented in RAC Select component, using a mouse or keyboard triggers data-focused on the selector. The styling for &[data-focused] in the recipe is what styles the focus ring and so it makes sense to remove it.
• Keyboard focus is unaffected after removing this style, because styling for &[data-focus-visible] handles the keyboard case. As documented in RAC Select component, [data-focus-visible] is used when select is specifically keyboard focused.
• Despite what the comment says, removing styling doesn't seem to change the behaviour of the ComboBox.

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Going to fix #39 here as well