fix: Additional Salary component amount not getting set (#25356)

diff --git a/erpnext/payroll/doctype/salary_slip/salary_slip.py b/erpnext/payroll/doctype/salary_slip/salary_slip.py
index 539f2c5..afdf081 100644
--- a/erpnext/payroll/doctype/salary_slip/salary_slip.py
+++ b/erpnext/payroll/doctype/salary_slip/salary_slip.py
@@ -633,6 +633,8 @@
 
 		if additional_salary:
 			component_row.default_amount = 0
+			component_row.additional_amount = amount
+			component_row.additional_salary = additional_salary.name
 			component_row.deduct_full_tax_on_selected_payroll_date = \
 				additional_salary.deduct_full_tax_on_selected_payroll_date
 		else: