Administration: Consistent styling for site icon setting.

In General Settings, set the `remove-site-icon` class in initial state and add border for clearer control boundaries.

Props sabernhardt, noruzzaman, madhavishah01, huzaifaalmesbah, hmbashar, shailu25, joedolson.
Fixes #64736.

git-svn-id: https://develop.svn.wordpress.org/trunk@61770 602fd350-edb4-49c9-b593-d223f7449a82

Author: joedolson

src/wp-admin/css/site-icon.css

@@ -181,7 +181,7 @@
 button.reset.remove-site-icon {
 	color: var(--site-icon-removal);
 	text-decoration: none;
-	border-color: transparent;
+	border-color: currentColor;
 	box-shadow: none;
 	background: transparent;
 }

src/wp-admin/options-general.php

@@ -202,7 +202,7 @@ class="<?php echo esc_attr( $classes_for_button ); ?>"
 		<button
 			id="js-remove-site-icon"
 			type="button"
-			<?php echo has_site_icon() ? 'class="button button-secondary reset remove-site-icon"' : 'class="button button-secondary reset hidden"'; ?>
+			<?php echo has_site_icon() ? 'class="button button-secondary reset remove-site-icon"' : 'class="button button-secondary reset remove-site-icon hidden"'; ?>
 		>
 			<?php _e( 'Remove Site Icon' ); ?>
 		</button>