fix(TaskProcessing): increase task cleanup delay

[edward-ly]

• Resolves: Increase task cleanup delay assistant#223

Summary

It is currently 4 weeks. It could be raised to 4 months.

There a bit of a compromise to find. Designers want the tasks to be kept forever and engineers want to cleanup soon to save storage space and DB.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[edward-ly]

/backport to stable31

[edward-ly]

/backport to stable30

[provokateurin]

🤷‍♀️

[jancborchardt]

@julien-nc @edward-ly if it’s still limited, could we have a notice in the interface somewhere about this? E.g. in the same place as the "This is AI-generated, please double check" notice we also need?
(Just for the record, as said in the topic also, I’d rather have it not limited.)