After upgrade to 5.0.2 single run tasks aren't running

I use a single run task for my migrations, but after upgrading from 4.6.3 to 5.0.2 the single run task isn't running.

The task is created, but it doesn't execute the command.

Start by reproducing the single-run migration task behavior across versions 4.6.3 and 5.0.2, then trace where the task is created and where its command should execute. Done means the configured command runs once after the upgrade, with a regression test covering the behavior.

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