Fix sometimes not resetting media position

[ByteHamster]

Description

Before 5218e06, deleting an item loaded its state from the database again. Now it stores the state of that object. markItemPlayed() did not reset the object's playback position, so when auto-delete was enabled, the position was overwritten again.

Closes #7092

Checklist

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• If it is a core feature, I have added automated tests