Add a Reference of Original Sales Estimate in Converted Invoices

[anuj-ever]

Issue:

Currently, when a sales estimate is converted to a sales invoice, there is no reference back to the original estimate. This makes it difficult for users to trace the payment back to its initial proposal, causing potential confusion and gaps in the audit trail.

Expected Condition:

When a sales estimate is converted to a sales invoice, there should be a clear reference back to the original sales estimate. This will allow users to easily trace payments and understand the history of the transaction, ensuring comprehensive documentation and better financial tracking.

Supporting Document: