Fix sticky header is terminated earlier than it should because of the margin in the header element (#20275)

GitOrigin-RevId: 35e9e9c5a0212019b27d5090627c20cec1e7575a

services/web/frontend/stylesheets/app/plans/plans-new-design.less

@@ -861,14 +861,12 @@
           padding: unset;
 
           .plans-features-table-header-item-content-mobile {
-            margin-bottom: var(--spacing-08);
             padding: var(--spacing-04);
             text-align: center;
             background-color: var(--neutral-10);
           }
 
           .plans-group-features-table-header-item-content-mobile {
-            margin-bottom: var(--spacing-08);
             padding: var(--spacing-04);
             text-align: center;
             background-color: var(--neutral-10);
@@ -908,6 +906,10 @@
         }
       }
 
+      tr.plans-features-table-row-for-margin {
+        height: var(--spacing-08);
+      }
+
       .plans-features-table-body-container-mobile {
         .plans-features-table-row-heading-mobile {
           font-weight: 600;