Fix keyboard navigation on search pages

Some of our search pages (such as the room and user search) has a list
header item. Due to how this works, it's not actually a part of the
list view keyboard navigation and a whole separate item. So in the tab
order, it comes *after* the list view which makes no sense. And it's
part of the list view, so users must expect it to be selectable with the
up and down arrows like other items.

This simple change makes it so it behaves as expected. The first actual
list item is selected by default, but it's possible to navigate to the
list header item via the up arrow key and then return to the list view
using the down arrow. The list header item is also removed from the tab
order and the whole page is much nicer to use now.

src/qml/ExploreRoomsPage.qml

@@ -89,6 +89,7 @@ SearchPage {
     listHeaderDelegate: Delegates.RoundedItemDelegate {
         onClicked: _private.openManualRoomDialog()
 
+        activeFocusOnTab: false // We handle moving to this item via up/down arrows, otherwise the tab order is wacky
         text: i18n("Enter a room address")
         icon.name: "compass"
         icon.width: Kirigami.Units.gridUnit * 2

src/qml/SearchPage.qml

@@ -174,5 +174,14 @@ Kirigami.ScrollablePage {
             anchors.centerIn: parent
             visible: searchField.text.length > 0 && listView.count === 0 && root.model.searching
         }
+
+        Keys.onUpPressed: {
+            if (listView.currentIndex > 0) {
+                listView.decrementCurrentIndex();
+            } else {
+                listView.currentIndex = -1; // This is so the list view doesn't appear to have two selected items
+                listView.headerItem.forceActiveFocus(Qt.TabFocusReason);
+            }
+        }
     }
 }

src/qml/UserSearchPage.qml

@@ -42,6 +42,7 @@ SearchPage {
     listHeaderDelegate: Delegates.RoundedItemDelegate {
         onClicked: _private.openManualUserDialog()
 
+        activeFocusOnTab: false // We handle moving to this item via up/down arrows, otherwise the tab order is wacky
         text: i18n("Enter a user ID")
         icon.name: "list-add-user"
         icon.width: Kirigami.Units.gridUnit * 2