Format Library: Fix logic on hasColorsToChoose (#65530)

Previous logic showed unusable Highlight format when palette was empty and custom was disabled, and hid it when custom was enabled but palette was empty.

Co-authored-by: dougwollison <dougwollison@git.wordpress.org>
Co-authored-by: Mamaduka <mamaduka@git.wordpress.org>

packages/format-library/src/text-color/index.js

@@ -75,7 +75,7 @@ function TextColorEdit( {
 		[ contentRef, value, colors ]
 	);
 
-	const hasColorsToChoose = colors.length || ! allowCustomControl;
+	const hasColorsToChoose = !! colors.length || allowCustomControl;
 	if ( ! hasColorsToChoose && ! isActive ) {
 		return null;
 	}