Fix transparent background after upgrade of spectrum color picker (#14251)

src/Umbraco.Web.UI.Client/src/less/components/umb-color-picker.less

@@ -1,19 +1,15 @@
-.umb-color-picker {
+.umb-color-picker {
 
     .sp-replacer {
         display: inline-flex;
         margin-right: 12px;
         height: 32px;
+        padding: 5px;
 
         &.sp-light {
             background-color: @white; 
         }
 
-        .sp-preview {
-            margin: 5px;
-            height: auto;
-        }
-
         .sp-dd {
             line-height: 2rem;
         }
@@ -24,4 +20,4 @@
     .sp-replacer {
         cursor: not-allowed;
     }
-}
+}