Make fullscreen images focused when they're opened

Otherwise keyboard shortcuts don't work until you tap the image, which
makes no sense.

BUG: 484322
(cherry picked from commit a41d0f3214)

src/qml/NeochatMaximizeComponent.qml

@@ -104,6 +104,8 @@ Components.AlbumMaximizeComponent {
         }
     }
 
+    onOpened: forceActiveFocus()
+
     onItemRightClicked: RoomManager.viewEventMenu(root.currentEventId, root.currentRoom)
 
     onSaveItem: {

src/qml/QrCodeMaximizeComponent.qml

@@ -14,6 +14,8 @@ Components.AbstractMaximizeComponent {
     property color avatarColor
     required property string avatarSource
 
+    onOpened: forceActiveFocus()
+
     Shortcut {
         sequences: [StandardKey.Cancel]
         onActivated: root.close()