action-list: Take items with css propery display:contents into account

The list items of icingadb/(hostgroups/servicegroups) have the css property `display:contents`, which leads to the scrollIntoView() function having no effect.

public/js/action-list.js

@@ -432,9 +432,15 @@
          * @param pressedKey Pressed key (`ArrowUp` or `ArrowDown`)
          */
         scrollItemIntoView(item, pressedKey) {
-            item.scrollIntoView({block: "nearest"});
             let directionalNext = this.getDirectionalNext(item, pressedKey);
 
+            if (item.parentElement.hasAttribute('data-is-display-contents')) {
+                item = item.firstChild;
+                directionalNext = directionalNext ? directionalNext.firstChild : null;
+            }
+
+            item.scrollIntoView({block: "nearest"});
+
             if (directionalNext) {
                 directionalNext.scrollIntoView({block: "nearest"});
             }
@@ -737,6 +743,30 @@
                 list = _this.findDetailUrlActionList(container);
             }
 
+            if (! list || ! list.hasAttribute('data-is-display-contents')) {
+                // no detail view || not checked before
+                let actionLists = null;
+                if (! list) {
+                    actionLists = document.querySelectorAll('.action-list');
+                } else {
+                    actionLists = [list];
+                }
+
+                for (let actionList of actionLists) {
+                    let firstSelectableItem = actionList.querySelector(':scope > [data-action-item]');
+                    if (
+                        firstSelectableItem
+                        && (
+                            ! firstSelectableItem.checkVisibility()
+                            && firstSelectableItem.firstChild
+                            && firstSelectableItem.firstChild.checkVisibility()
+                        )
+                    ) {
+                        actionList.dataset.isDisplayContents = "";
+                    }
+                }
+            }
+
             if (list && list.matches('[data-icinga-multiselect-url], [data-icinga-detail-url]')) {
                 let detailUrl = _this.icinga.utils.parseUrl(
                     _this.icinga.history.getCol2State().replace(/^#!/, '')