Fix: Color formatter appears when color choosing is not possible

[jorgefilipecosta]

Fix: #20205

This PR makes sure we don't show the color formatter if the user has no colors to choose from.

How has this been tested?

I used the custom color formatter and added some colors to a paragraph and saved the post.
I added this code to the functions.php section of the currently enabled theme:

function set_colors() {
	add_theme_support( 'editor-color-palette', array() );
	add_theme_support( 'disable-custom-colors' );
}

add_action( 'after_setup_theme', 'set_colors' );

I verified the color formatter was not enabled to add colors to new parts of the text.
I verified the color formatter still appeared on the parts of the text with a color previously enabled and I verified that if I click the formatter the color is removed.