Issue #3291764: The [0] hatch in misc/vertical-tabs.js causes issues if there...

Issue #3291764: The [0] hatch in misc/vertical-tabs.js causes issues if there are multiple forms with vertical tabs

Closes #3291764

core/misc/vertical-tabs.js

@@ -196,8 +196,11 @@
         })
         .end()
         .show()
-        .siblings(':hidden.vertical-tabs__active-tab')[0].value =
-        this.details.attr('id');
+        .siblings(':hidden.vertical-tabs__active-tab')
+        .get()
+        .forEach((hidden) => {
+          hidden.value = this.details.attr('id');
+        });
       this.details.attr('open', true);
       this.item.addClass('is-selected');
       // Mark the active tab for screen readers.