FINERACT-2649: Migrate Tier 4 loan integration tests to Feign client

[DeathGun44]

Summary

Migrates the next batch of loan integration tests from the legacy REST-assured helpers to the typed Feign client.

Scope (25 commits on top of s3)

• Loan account, product, GL-account and API tests
• Advanced payment allocation schedule test
• Initiate external asset owner transfer test
• Batch API integration test
• Loan interest payment waiver test
• Delinquency buckets integration test
• External business event test
• Loan accrual activity / submitted-date tests
• Loan specific-due-date charge tests
• User loan permission test
• SQL injection reporting test (Feign raw HTTP)
• External asset owner transfer / cancel / search tests
• Inline loan COB test
• COB partitioning test
• Loan COB account-lock catch-up inline COB test
• Loan catch-up integration test
• Penalty, journal-reversal and batch loan tests
• External asset owner tests
• Loan capitalized-income, buy-down and charge-off tests
• Loan interest refund, pause and point-in-time tests
• Delinquency and event tests
• Loan COB and interest-recalculation tests
• Loan accrual and disbursement-schedule tests
• Loan charge tests
• Client loan integration test

New helpers / infra

• FeignBatchHelper, FeignBusinessStepHelper, FeignExternalAssetOwnerHelper, FeignFundHelper, FeignLoanCOBCatchUpHelper, FeignUserHelper
• InternalLoanReAgeApi, InternalConfigurationsApi
• Additional methods on FeignLoanTestBase, FeignTransactionHelper, FeignLoanHelper

Stacked on

• FINERACT-2649: Migrate Tier 3 loan integration tests to Feign client #6084 (s3)