Missing color picker's clear-button styling

[Cybr]

Hello!

I noticed that when the WordPress color picker is created without a default value, the "clear" button shows up instead. That's great!

The problem is that it isn't styled, so the button isn't aligned correctly.

To resolve this, the clear button's class (.wp-picker-input-wrap .button.wp-picker-clear) should have the same styles as the default button's class (.wp-picker-input-wrap .button.wp-picker-default).

[Cybr]

I couldn't find the /wp-admin/css/color-picker-rtl.css stylesheet in the SVN repo. But the same changes should be implemented for those.

[SergeyBiryukov]

In 47433:

Customize: Ensure color picker's Clear button is aligned properly.

Props Cybr.
Fixes #49543.