Issue: Fix UCS address precedence order for payment method billing addresses

## Problem

The current implementation in the UCS (Unified Connector Service) transformers has incorrect precedence order when handling addresses. The unified payment method billing address should take priority over the shipping/billing addresses from the payment request.

## Current Behavior

- Shipping address: `shipping.or(unified_payment_method_billing.clone())`
- Billing address: `billing.or(unified_payment_method_billing)`

This means the payment request addresses take precedence over the unified payment method billing address.

## Expected Behavior

The unified payment method billing address should take precedence:

- Shipping address: `unified_payment_method_billing.clone().or(shipping)`
- Billing address: `unified_payment_method_billing.or(billing)`

## Impact

This affects address data consistency in UCS transformations and could lead to incorrect address information being sent to connectors.

## Files Affected

- `crates/router/src/core/unified_connector_service/transformers.rs`

Resolution: <think>
PR Context:
- Title: fix: change precedence order in address that we send to ucs
- Merged: 2025-09-03T17:28:26Z
- Files changed: 1 files
- Commits: 3 commits

Implementation approach:
## Summary

This PR fixes the billing address precedence order in the UCS (Unified Connector Service) transformers to ensure that unified payment method billing addresses take priority over billing addresses from payment requests.

## Changes

- Changed billing address precedence: `unified_payment_method_billing.or(billing)` instead of `billing.or(unified_payment_method_billing)`
- Shipping address logic remains unchanged: `shipping`

## Related Issues

- Closes #9268: Fix UCS address
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** fix: change precedence order in address that we send to ucs (#9269)
Files to modify:


**crates/router/src/core/unified_connector_service/transformers.rs**
  Modify existing code