Fix auto sleep timer & initial migration for synced tasks

[GianniCarlo]

Bugfix

• Fix auto sleep timer being reset after changing a chapter on a bound book, or when the next books is autoplayed
• Fix Realm migration for queued task with invalid value type for the last played timestamp (related to the fix on v5.2.4)

Related tasks

#1104

Approach

• Make a distinction for the play function when something is autoplayed, and when it's from user input to trigger the auto sleep timer reset
• Catch string values in the Realm migrations for the last played timestamp, and override with 0