Fix qml Audio/Video support in qt6 too.

in Audio qt6 we don't have autoload feature but we disable it in qt5 => it seems ok

In Video qml qt6 we don't have flushMode.

src/qml/Component/Timeline/AudioDelegate.qml

@@ -4,7 +4,7 @@
 import QtQuick 2.15
 import QtQuick.Controls 2.15 as QQC2
 import QtQuick.Layouts 1.15
-import QtMultimedia 5.15
+import QtMultimedia @QTMULTIMEDIA_MODULE_QML_VERSION@ 
 
 import org.kde.kirigami 2.15 as Kirigami
 
@@ -42,10 +42,10 @@ TimelineContainer {
         Layout.fillWidth: true
         Layout.maximumWidth: root.contentMaxWidth
 
-        Audio {
+        @QTMULTIMEDIA_AUDIO@ {
             id: audio
             source: root.progressInfo.localPath
-            autoLoad: false
+            @QTMULTIMEDIA_AUDIO_AUTOLOAD@
         }
 
         states: [

src/qml/Component/Timeline/VideoDelegate.qml

@@ -4,7 +4,7 @@
 import QtQuick 2.15
 import QtQuick.Controls 2.15 as QQC2
 import QtQuick.Layouts 1.15
-import QtMultimedia 5.15
+import QtMultimedia @QTMULTIMEDIA_MODULE_QML_VERSION@ 
 import Qt.labs.platform 1.1 as Platform
 
 import org.kde.kirigami 2.13 as Kirigami
@@ -124,7 +124,7 @@ TimelineContainer {
         Layout.preferredHeight: videoHeight
 
         fillMode: VideoOutput.PreserveAspectFit
-        flushMode: VideoOutput.FirstFrame
+        @QTMULTIMEDIA_VIDEO_FLUSHMODE@
 
         states: [
             State {