fix: asset WDV depreciation calc according to IT act [v14]

[anandbaburajan]

First year depreciation for WDV method as per Income Tax act wasn't being calculated properly. Now the depreciation calculations in ERPNext match these calculations provided by a customer.

Needs to be merged with: frappe/erpnext#39050.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (91cc767) 56.58% compared to head (63f01ef) 56.54%.
Report is 10 commits behind head on version-14-hotfix.

❗ Current head 63f01ef differs from pull request most recent head ccb5bc0. Consider uploading reports for the commit ccb5bc0 to get more accurate results

Additional details and impacted files

@@                  Coverage Diff                  @@
##           version-14-hotfix    #1520      +/-   ##
=====================================================
- Coverage              56.58%   56.54%   -0.05%     
=====================================================
  Files                     98       98              
  Lines                   7832     7842      +10     
=====================================================
+ Hits                    4432     4434       +2     
- Misses                  3400     3408       +8     

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