refactor: rename 'Unreconcile Payments' doctype to singular 'Unreconcile Payment'

[ruthra-kumar]

#38238

[codecov]

Codecov Report

Merging #38258 (74f9e34) into develop (fb06ad7) will increase coverage by 0.00%.
Report is 42 commits behind head on develop.
The diff coverage is 57.89%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop   #38258   +/-   ##
========================================
  Coverage    67.26%   67.27%           
========================================
  Files          757      757           
  Lines        60502    60515   +13     
========================================
+ Hits         40698    40709   +11     
- Misses       19804    19806    +2     

Files	Coverage Δ
...xt/accounts/doctype/payment_entry/payment_entry.py	83.66% <ø> (ø)
...xt/accounts/doctype/sales_invoice/sales_invoice.py	83.83% <ø> (-0.08%)	⬇️
erpnext/accounts/party.py	81.02% <ø> (ø)
erpnext/controllers/sales_and_purchase_return.py	87.18% <100.00%> (+0.04%)	⬆️
erpnext/controllers/taxes_and_totals.py	95.30% <100.00%> (ø)
erpnext/hooks.py	100.00% <ø> (ø)
...serial_and_batch_bundle/serial_and_batch_bundle.py	73.15% <ø> (ø)
erpnext/stock/report/item_prices/item_prices.py	94.80% <ø> (ø)
...doctype/unreconcile_payment/unreconcile_payment.py	55.73% <50.00%> (ø)
.../report/accounts_receivable/accounts_receivable.py	89.68% <75.00%> (ø)
... and 3 more

... and 5 files with indirect coverage changes

[ruthra-kumar]

defer backport for a day or two