Deadlock Detected in bulk update payments.

[hemant10yadav]

CCCT-549

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• The deadlock error indicates that two separate transactions were trying to access the same data in conflicting orders, even though the code is using a single transaction.atomic() block.
• This suggests there are concurrency issues beyond just the single transaction, likely due to the fact that this is a Celery task.
• The transaction.atomic() block only ensures atomicity within a single Celery task, but does not prevent deadlocks between multiple concurrent tasks.

To resolve this, I have moved the task that updates the payment date work into another transaction.atomic() block. This can help reduce contention and the likelihood of deadlocks.