fix: pass order_id and store transaction ID in Braintree integration

[miteshpc]

Description

The Braintree integration in braintree_settings.py omits two critical fields when processing transactions:

1. order_id is never sent to Braintree despite being available in self.data. The Braintree Transaction Sale API accepts order_id as a standard field (see [Braintree Transaction API](https://developer.paypal.com/braintree/docs/reference/request/transaction/sale)), allowing merchants to store a reference identifier against each transaction visible in the Braintree merchant dashboard and searchable via the API. Without this, there is no way to trace a Braintree transaction back to the originating ERPNext Payment Request from the Braintree side.

2. The Braintree transaction ID is never persisted in ERPNext. On success, result.transaction.id is discarded and only result.transaction.status is stored in the Integration Request output field. This makes it impossible to cross-reference an ERPNext Integration Request with a Braintree transaction.

Changes

• Pass self.data.order_id (the Payment Request name) as order_id in the braintree.Transaction.sale() call
• Store result.transaction.id instead of result.transaction.status in the Integration Request output field on success

Before

result = braintree.Transaction.sale(
    {
        "amount": self.data.amount,
        "payment_method_nonce": self.data.payload_nonce,
        "options": {"submit_for_settlement": True},
    }
)
# ...
self.integration_request.db_set("output", result.transaction.status, update_modified=False)

After

result = braintree.Transaction.sale(
    {
        "amount": self.data.amount,
        "payment_method_nonce": self.data.payload_nonce,
        "order_id": self.data.order_id,
        "options": {"submit_for_settlement": True},
    }
)
# ...
self.integration_request.db_set("output", result.transaction.id, update_modified=False)

---

Test Scenario

Enable Approver / Reviewer Steps

1. Configure a Braintree sandbox account with valid credentials in Braintree Settings
2. Create a Sales Invoice and generate a Payment Request from it (e.g. PAY-REQ-2024-00001)
3. Open the payment link and complete a test transaction using Braintree's sandbox card 4111111111111111
4. In your Braintree sandbox merchant dashboard, navigate to Transactions and open the completed transaction
5. Verify that the Order ID field shows PAY-REQ-2024-00001 — matching the Payment Request name in ERPNext
6. In ERPNext, open the Integration Request log created for this transaction
7. Verify that the Output field contains the Braintree transaction ID (e.g. 7kg3qt) rather than a status string like submitted_for_settlement
8. Cross-reference: search for the transaction in Braintree by Order ID and confirm it returns the correct transaction

Reference

• Braintree Transaction Sale API — order_id field — max 255 characters, 127 for PayPal transactions
• Braintree Transaction Search — order_id as searchable field

[miteshpc]

Request to be backported to version-15