fix: incorrect tax calculation in case of reduced payment days

[ruchamahabal]

Problem:

After frappe/erpnext#31521 components dependent on other components (based on payment days) started getting updated values while setting up "default amount" itself.

This leads to incorrect TDS calculations for employees with lesser payment days in the current month. TDS considers the default amount (without payment days) while calculating the taxable amount.

Structure:

Salary Slip for the employee with DOJ 4/7/22 = 28/31 payment days:

Fix:

Keep a track of default amounts for components to update default amounts for dependent components.

[codecov-commenter]

Codecov Report

Merging #31 (44e1dd4) into develop (47f8a81) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop      #31   +/-   ##
========================================
  Coverage    71.80%   71.81%           
========================================
  Files          174      174           
  Lines         8655     8658    +3     
========================================
+ Hits          6215     6218    +3     
  Misses        2440     2440           

Impacted Files	Coverage Δ
hrms/payroll/doctype/salary_slip/salary_slip.py	87.18% <100.00%> (+0.04%)	⬆️