[16.0][ADD] l10n_th_account_tax_netting

[Saran440]

This module supports users who utilize both account_payment_netting and l10n_th_account_tax within the same project.
However, the current calculation of withholding tax (WHT) is incorrect because it only considers the payment side.

Case 1 : Payment with AP > AR but AR has withholding tax

• AP 200฿
• AR 100฿ (WHT 3%)

When users net invoices, it incorrectly pays 97฿. The correct amount should be 103฿, including a 3฿ withholding tax.

Case 2 : Payment with AR > AP but AP has withholding tax

• AP 100฿ (WHT 3%)
• AR 200฿

When users net invoices, it incorrectly receives 97฿. The correct amount should be 103฿, including a 3฿ withholding tax.

DEPENDS ON:

• [16.0][MIG] account_payment_netting account-financial-tools#1792

TODO:

• Test Script
• Readme

[github-actions]

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