fix: broken advance field in Accounts Receivable summary rpt

[ruthra-kumar]

Advance amount field in Accounts Receivable Summary wasn't getting populated. This is fixed by Querying Payment Ledger for unallocated Advances.

Todo:

• Add Tests

before:

after:

[codecov]

Codecov Report

Merging #36727 (0dc5e5c) into develop (8601e5b) will increase coverage by 0.12%.
Report is 38 commits behind head on develop.
The diff coverage is 75.00%.

❗ Current head 0dc5e5c differs from pull request most recent head af52f21. Consider uploading reports for the commit af52f21 to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #36727      +/-   ##
===========================================
+ Coverage    64.82%   64.95%   +0.12%     
===========================================
  Files          792      792              
  Lines        61798    61826      +28     
===========================================
+ Hits         40063    40157      +94     
+ Misses       21735    21669      -66     

Files Changed	Coverage Δ
...ype/pos_invoice_merge_log/pos_invoice_merge_log.py	79.80% <ø> (ø)
..._receivable_summary/accounts_receivable_summary.py	0.00% <ø> (ø)
erpnext/accounts/utils.py	73.98% <ø> (ø)
erpnext/accounts/party.py	78.01% <14.28%> (+0.60%)	⬆️
...xt/accounts/doctype/payment_entry/payment_entry.py	83.50% <87.50%> (-0.22%)	⬇️
...rpnext/accounts/doctype/pos_invoice/pos_invoice.py	73.37% <100.00%> (+0.09%)	⬆️
...serial_and_batch_bundle/serial_and_batch_bundle.py	71.15% <100.00%> (-0.06%)	⬇️

... and 8 files with indirect coverage changes