autoremove: skip formulae where installed_on_request is nil

[Rylan12]

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Fixes #17572

This PR modifies the autoremove formula detection logic to only include formulae who's tab installed_on_request value is false. This is to prevent autoremove from removing formulae that have malformed install receipts which make us unsure whether they were actually installed on request or not. Instead, let's err on the side of caution and not remove the formula.

[apainintheneck]

Better safe than sorry. It'd be great to figure out why the installed_on_request field would be null though. Is this still something that can happen with new install receipts or is it legacy behavior that's been fixed in the meantime?

[Rylan12]

Yeah, it would be good to find how it happened, but my initial attempt wasn't fruitful. Do you have any ideas?

[MikeMcQuaid]

Is this still something that can happen with new install receipts or is it legacy behavior that's been fixed in the meantime?

This is something that can just happen with very old tabs.