Fix sometimes not resetting media position

[ByteHamster]

Description

Before 5218e06904e489f77da4078de775dd0a63b94ef4, 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

• [x] I have read the contribution guidelines: https://github.com/AntennaPod/AntennaPod/blob/develop/CONTRIBUTING.md#submit-a-pull-request
• [x] I have performed a self-review of my code
• [x] I have run the automated code checks using ./gradlew checkstyle spotbugsPlayDebug spotbugsDebug :app:lintPlayDebug
• [x] My code follows the style guidelines of the AntennaPod project: https://github.com/AntennaPod/AntennaPod/wiki/Code-style
• [x] I have mentioned the corresponding issue and the relevant keyword (e.g., "Closes: #xy") in the description (see https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue)
• [x] If it is a core feature, I have added automated tests