Customizer: Contain "No image set/selected" in dashed border.

Props Ankit K Gupta, chris_dev.
Fixes #35826.

git-svn-id: https://develop.svn.wordpress.org/trunk@36639 602fd350-edb4-49c9-b593-d223f7449a82

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

@@ -807,6 +807,11 @@ p.customize-section-description {
 	position: relative;
 	text-align: center;
 	cursor: default;
+	border: 1px dashed #b4b9be;
+	-webkit-box-sizing: border-box;
+	-moz-box-sizing: border-box;
+	box-sizing: border-box;
+	min-height: 40px;
 }
 
 .customize-control-media .inner,
@@ -844,7 +849,7 @@ p.customize-section-description {
 .customize-control-header .inner,
 .customize-control-header .inner .dashicons {
 	line-height: 20px;
-	top: 10px;
+	top: 8px;
 }
 
 .customize-control-header .list .inner,

src/wp-includes/js/customize-views.js

@@ -63,9 +63,7 @@
 		setPlaceholder: function(_height) {
 			var height = _height || this.getHeight();
 			this.model.set('savedHeight', height);
-			this.$el
-				.add(this.$el.find('.placeholder'))
-				.height(height);
+			this.$el.height(height);
 		},
 
 		setButtons: function() {