[18.0][FIX] payroll_account: Fix _get_partner_id logic in hr_payslip_line

[hussain]

Description

This PR fixes the partner logic in hr_payslip_line._get_partner_id() to address issue #221 where journal entries were created without proper partner information in Odoo 17.0+.

Problem

The original logic had several issues:

1. Odoo removed field address_home_id from model hr.employee which was used in getting partner for employee in payroll_account to set partner in created journal entry. Migrated code removed usage of address_home_id but did not use a replacement.
2. Old code (16.0 and earlier) used a confusing fallback chain that could potentially assign wrong partners
3. Missing liability_current account type in partner-required accounts

Solution

Replaced the flawed logic with semantically-correct partner assignment using the proper partner source:

• asset_receivable & liability_current: Always use employee partner (work_contact_id → bank_account_id.partner_id)
• liability_payable: Always use register partner (salary_rule_id.register_id.partner_id)
• Other account types (expense, income, etc.): No partner assigned

Changes

Core Logic (payroll_account/models/hr_payslip_line.py)

• Simplified logic from confusing fallback to clear semantic rules
• Added liability_current to partner-required account types
• Enhanced documentation with business semantics and partner sources
• Replaced if register_partner_id or acc_type in (...) with proper if elif structure

Business Logic

Account Type	Business Use	Partner Source
asset_receivable	Employee loans, advances	Employee
liability_current	Employee salary payable	Employee
liability_payable	Tax authorities, insurance	Register Partner
expense, income, etc.	Internal accounting	No Partner

Test Coverage

Added test_partner_logic_account_types() to verify:

• asset_receivable accounts return employee partner
• liability_current accounts return employee partner
• liability_payable accounts return register partner
• Other account types return False (no partner)

Fixes #221

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Pull Request opened by Augment Code with guidance from the PR author

[OCA-git-bot]

Hi @nimarosa, @appstogrow, some modules you are maintaining are being modified, check this out!