feat: add total_billing_hours to Sales Invoice (fp #26783)

[frappe-pr-bot]

Backport 09ccdee from #27742

⚠️ CONFLICTS detected ⚠️
Please resolve conflicts and verify diff with original PR before merging.

[codecov]

Codecov Report

Merging #27773 (09ccdee) into version-13-hotfix (cc143bc) will decrease coverage by 0.14%.
The diff coverage is 22.85%.

❗ Current head 09ccdee differs from pull request most recent head 77e4408. Consider uploading reports for the commit 77e4408 to get more accurate results

@@                  Coverage Diff                  @@
##           version-13-hotfix   #27773      +/-   ##
=====================================================
- Coverage              54.62%   54.47%   -0.15%     
=====================================================
  Files                   1334     1248      -86     
  Lines                  70756    67518    -3238     
=====================================================
- Hits                   38650    36781    -1869     
+ Misses                 32106    30737    -1369     

Impacted Files	Coverage Δ
...of_accounts_importer/chart_of_accounts_importer.py	0.00% <0.00%> (ø)
erpnext/controllers/queries.py	60.32% <ø> (+1.79%)	⬆️
erpnext/accounts/utils.py	59.38% <21.42%> (-0.33%)	⬇️
...xt/accounts/doctype/payment_entry/payment_entry.py	69.59% <50.00%> (-0.04%)	⬇️
...xt/accounts/doctype/sales_invoice/sales_invoice.py	76.79% <100.00%> (+1.36%)	⬆️
erpnext/utilities/product.py	15.94% <0.00%> (-34.79%)	⬇️
erpnext/hr/doctype/job_applicant/job_applicant.py	48.21% <0.00%> (-32.35%)	⬇️
...wise_balance_history/batch_wise_balance_history.py	69.49% <0.00%> (-23.73%)	⬇️
erpnext/shopping_cart/product_info.py	32.35% <0.00%> (-20.59%)	⬇️
...eport/item_variant_details/item_variant_details.py	84.52% <0.00%> (-3.58%)	⬇️
... and 73 more