MediaPlayer crashes on seek after loop reset.

Steps to reproduce:

1. Open the MediaPlayer demo application
2. Open a video
3. Play video and set the loop mode to infinite loop
4. After video has looped over once, set the loop mode to no loop
5. Seek ahead on the video using the timeline

Expected:

Video playback position is changed normally

Actual:

Application crashes on following assertion:

ASSERT: "loops < 0 || m_posWithOffset.offset.index < loops" in file ~/qt6/qtmultimedia/src/plugins/multimedia/ffmpeg/playbackengine/qffmpegdemuxer.cpp, line 42

Debugger breakpoint on failed assertion shows loops as 1 and m_posWithoffset.offset.index as 1.