feat: add Partly Paid status in Invoices

[sagarvora]

• Resolves Mark Sales Invoice as Overdue when first payment becomes overdue #26969
• Also uses getdate() instead of CURDATE() to get accurate dates based on timezones set in System Settings.

Behaviour

If a part of the invoice amount has been received, Partly Paid state will be shown (instead of Unpaid). If any scheduled payment (as specified in the Payment Schedule table) is pending beyond it's due date, the Overdue state will be shown.

Documentation

https://docs.erpnext.com/docs/v13/user/manual/en/accounts/purchase-invoice/edit?wiki_page_patch=a8b85aba51
https://docs.erpnext.com/docs/v13/user/manual/en/accounts/sales-invoice/edit?wiki_page_patch=709cb5df15

Reopened from #27310

[codecov]

Codecov Report

Merging #27625 (2deb312) into develop (2af6ea6) will increase coverage by 0.07%.
The diff coverage is 88.46%.

❗ Current head 2deb312 differs from pull request most recent head 7841083. Consider uploading reports for the commit 7841083 to get more accurate results

@@             Coverage Diff             @@
##           develop   #27625      +/-   ##
===========================================
+ Coverage    54.50%   54.58%   +0.07%     
===========================================
  Files         1333     1333              
  Lines        70731    70736       +5     
===========================================
+ Hits         38553    38611      +58     
+ Misses       32178    32125      -53     

Impacted Files	Coverage Δ
erpnext/controllers/accounts_controller.py	83.65% <0.00%> (ø)
...xt/accounts/doctype/sales_invoice/sales_invoice.py	75.42% <94.73%> (+0.21%)	⬆️
...ounts/doctype/purchase_invoice/purchase_invoice.py	81.35% <100.00%> (-0.03%)	⬇️
erpnext/stock/report/stock_ledger/stock_ledger.py	78.33% <0.00%> (-2.50%)	⬇️
.../hr/doctype/upload_attendance/upload_attendance.py	45.11% <0.00%> (-1.51%)	⬇️
erpnext/portal/utils.py	30.00% <0.00%> (-1.43%)	⬇️
erpnext/stock/report/stock_ageing/stock_ageing.py	92.80% <0.00%> (-0.72%)	⬇️
.../report/accounts_receivable/accounts_receivable.py	67.90% <0.00%> (-0.44%)	⬇️
erpnext/selling/doctype/sales_order/sales_order.py	75.55% <0.00%> (-0.38%)	⬇️
...stock/doctype/purchase_receipt/purchase_receipt.py	90.34% <0.00%> (-0.27%)	⬇️
... and 19 more

[sagarvora]

Known Bug (not due to this PR)

When the cron job to update Overdue status in invoices runs, it sets the status for Sales Invoices that should've had the status Overdue and Discounted to simply Overdue