Add validation for banned and blacklisted custom fields.

This update enhances security by introducing checks for banned and blacklisted meta keys in custom fields. It includes CSS updates for admin builder styles and ensures banned fields are flagged accurately in the site health tool.

assets/css/admin/builder.css

@@ -495,6 +495,11 @@
   line-height: 18px;
   margin: 0 0 10px 0;
 }
+.um-admin-drag-col.cols-3 .um-admin-drag-fld-banned {
+  height: auto;
+  line-height: 18px;
+  margin: 0 0 10px 0;
+}
 .um-admin-drag-col.cols-3 .um-admin-drag-fld-icons {
   float: none;
   position: absolute;
@@ -600,6 +605,16 @@
   color: #fff;
 }
 
+.um-admin-drag-fld-banned {
+  float: left;
+  font-size: 13px;
+  height: 30px;
+  line-height: 30px;
+  margin: 0 0 0 20px;
+  font-weight: 400;
+  color: var(--um-blocks-error-color, #d92d20);
+}
+
 .um-admin-drag-fld-icons {
   float: right;
 }

assets/css/admin/builder.sass

@@ -400,6 +400,10 @@
       height: auto
       line-height: 18px
       margin: 0 0 10px 0
+    .#{$prefix}admin-drag-fld-banned
+      height: auto
+      line-height: 18px
+      margin: 0 0 10px 0
     .#{$prefix}admin-drag-fld-icons
       float: none
       position: absolute
@@ -492,6 +496,14 @@
   &.um-field-type-group
     color: #fff
 
+.#{$prefix}admin-drag-fld-banned
+  float: left
+  font-size: 13px
+  height: 30px
+  line-height: 30px
+  margin: 0 0 0 20px
+  font-weight: 400
+  color: $error-text
 
 .#{$prefix}admin-drag-fld-icons
   float: right