3437516 - Make chosen-single drop downs the same size as other drop downs

As shown in the issue, the chosen-single drop downs are a different size to other drop downs next to them, shift the padding from the class to the span to make these the same.

Closes #3437516

dist/css/components/chosen.css

@@ -12,13 +12,16 @@
   height: 100%;
   display: block;
   line-height: 1.5rem;
-  padding: calc(var(--gin-spacing-s) - 1px) calc(var(--gin-spacing-m) - 1px);
 }
 
 .form-element.chosen-container-single .chosen-single b {
   background: none !important;
 }
 
+.form-element.chosen-container-single .chosen-single span {
+  padding: calc(var(--input-padding-vertical) - 1px) var(--input-padding-horizontal);
+}
+
 .form-element.chosen-container-multi {
   width: auto !important;
 }