Refunds to reflect in Customer Monthly Revenue

[shubh24]

If a customer has been fully refunded in the same month as the transaction was made, the revenue entry in customer_monthly_revenue can show up as 0.

However, if If a customer has been fully refunded in a different month than the one in which the transaction was made, the revenue entry in customer_monthly_revenue in the two months should show up as +X and -X respectively.

Currently, the DBT models are not considering the second scenario -- and nullify the amount of all refunds irrespective of which month the refund was processed in.