fix(swap): correct misleading includeTx default value

[TaprootFreak]

Summary

Fixes misleading default value in createSwapPaymentInfo service method.

Problem

The service has includeTx = true as default:

async createSwapPaymentInfo(userId: number, dto: GetSwapPaymentInfoDto, includeTx = true)

But the controller always passes an explicit boolean:

this.swapService.createSwapPaymentInfo(jwt.user, dto, includeTx === 'true');

When no ?includeTx query parameter is provided:

• includeTx in controller = undefined
• undefined === 'true' = false

So the service default is never used, and the actual behavior is false.

Fix

Change default from true to false to accurately reflect actual behavior.

This is purely a code clarity fix - no functional change.

Test Plan

• No functional change - behavior stays the same
• CI passes