Issue #3526123: Fixed sticky table header issue when toolbar sticky disable,...

Issue #3526123: Fixed sticky table header issue when toolbar sticky disable, show on scroll-up enabled.

Closes #3526123

js/admin_toolbar.disable_sticky.js

+/**
+ * @file
+ * Admin Toolbar disable sticky behavior JS.
+ */
+
+(($, Drupal, once) => {
+  /**
+   * Implements the Admin Toolbar configured 'disabled sticky behavior'.
+   *
+   * @type {Drupal~behavior}
+   *
+   * @prop {Drupal~behaviorAttach} attach
+   *   Attaches the behavior to remove reset top offset.
+   */
+  Drupal.behaviors.adminToolbarDisableStickyBehavior = {
+    attach (context) {
+      if (context !== document) {
+        return;
+      }
+      // If toolbar 'stickyness' is disabled, the toolbar should not be
+      // included in the calculation of the top offset. Listen for the offset
+      // change event and remove data-offset-top attributes from toolbar-bar
+      // and any active toolbar-tray.
+      once('admin-toolbar-disable-sticky', 'body', context).forEach(() => {
+        $(document).on(
+          `drupalViewportOffsetChange`,
+          () => {
+            document.getElementById('toolbar-bar')
+              .removeAttribute('data-offset-top');
+
+            document.querySelector('.toolbar-tray.is-active')
+              ?.removeAttribute('data-offset-top');
+
+            // Trigger a recalculation of viewport displacing elements.
+            // Use setTimeout to ensure this recalculation happens after
+            // changes to visual elements have processed.
+            setTimeout(() => {
+              Drupal.displace(false);
+            }, "500");
+          },
+        );
+      });
+    },
+  };
+})(jQuery, Drupal, once);