Customizer: Fix layout issues in customizer accordions.

Adjust some CSS characteristics in the customizer accordions to avoid a slight horizontal scroll, allow the chevron icon to be part of the clickable control surface, and resolve a pre-existing padding issue allowing overflow on accordion headings.

Follow up to [59224].

Reviewed by desrosj, joedolson.
Merges [59409] to the 6.7 branch.

Props laurelfulford, wildworks, domainsupport, sabernhardt, rcreators, desrosj, sainathpoojary. 
Fixes #62313, #62335.

git-svn-id: https://develop.svn.wordpress.org/branches/6.7@59420 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/css/common.css

@@ -2462,7 +2462,7 @@ h1.nav-tab-wrapper, /* Back-compat for pre-4.4 */
 }
 .nav-menus-php .metabox-holder .accordion-section-title span.dashicons.dashicons-arrow-down::before {
 	position: relative;
-	left: -1px
+	left: -1px;
 }
 
 .nav-menus-php .metabox-holder .accordion-section.open .accordion-section-title span.dashicons.dashicons-arrow-down {

src/wp-admin/css/customize-controls.css

@@ -553,17 +553,19 @@ body.trashing #publish-settings {
 		.15s border-color ease-in-out;
 }
 
-.accordion-section-title:has(button.accordion-trigger) {
+.accordion-section-title:has(button.accordion-trigger),
+#customize-controls .current-panel .control-section > h3.accordion-section-title:has(button.accordion-trigger) {
 	padding: 0;
 }
 
 .accordion-section-title button.accordion-trigger {
 	all: unset;
 	width: 100%;
 	height: 100%;
-	padding: 10px 10px 11px 14px;
+	padding: 10px 30px 11px 14px;
 	display: flex;
 	align-items: center;
+	box-sizing: border-box;
 }
 
 .accordion-section-title button.accordion-trigger:has(.menu-in-location) {
@@ -587,6 +589,7 @@ body.trashing #publish-settings {
 #customize-outer-theme-controls .accordion-section-title:after {
 	content: "\f345";
 	color: #a7aaad;
+	pointer-events: none;
 }
 
 #customize-theme-controls .accordion-section-content,