Move resetting of counter from before_transition to after_transition

What does this MR do and why?

Move the reset of the counter at the beginning of a project artifact size refresh from before_transition to after_transition.

The reason is that the transition changes the status of the record. This status is used in other parts of the codebase to block certain APIs and services. For the blocking mechanism to work more reliably, the change in status must be committed, before the counter is reset.

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MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.

Related to #373469