fix: fetch item_tax_template values if fields with fetch_from exisit

[vorasmit]

Existing behaviour

• Function get_item_details fetches item tax template.
• There are no existing fields with fetch_from in the item tax template
• If a custom field is there with fetch_from in the item tax template, it's not fetched with item details

With this fix, it will support fetching custom fields (in item tax template) along with item details

Required for: resilient-tech/india-compliance#227

[codecov]

Codecov Report

Merging #38284 (b206b05) into develop (627165d) will increase coverage by 0.00%.
Report is 9 commits behind head on develop.
The diff coverage is 75.86%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop   #38284   +/-   ##
========================================
  Coverage    67.26%   67.27%           
========================================
  Files          757      757           
  Lines        60517    60550   +33     
========================================
+ Hits         40709    40734   +25     
- Misses       19808    19816    +8     

Files	Coverage Δ
erpnext/accounts/utils.py	73.33% <100.00%> (+0.16%)	⬆️
erpnext/controllers/accounts_controller.py	84.85% <100.00%> (+<0.01%)	⬆️
erpnext/stock/get_item_details.py	83.11% <100.00%> (+0.08%)	⬆️
...e/payment_reconciliation/payment_reconciliation.py	91.94% <65.00%> (-1.94%)	⬇️

... and 2 files with indirect coverage changes

[deepeshgarg007]

@vorasmit let us know when to backport this

[vorasmit]

Thank you for reviewing this.

This is independent and can be backported. Looking for this in v14 and 15.