chore: Fix a potential variable misuse bug

[LostBenjamin]

Hi,

This pull request is a fix to a potential variable misuse bug at erpnext/accounts/doctype/pricing_rule/pricing_rule.py. Please check the changes.

It seems to me that the variable in the if condition should be d to check if d is None. If the variable should indeed be field, it would be better to put the condition in a separate if statement.

Best,
Jingxuan

[codecov]

Codecov Report

Merging #31372 (ea1095f) into develop (86919d2) will increase coverage by 0.06%.
The diff coverage is 80.00%.

@@             Coverage Diff             @@
##           develop   #31372      +/-   ##
===========================================
+ Coverage    63.61%   63.67%   +0.06%     
===========================================
  Files          984      984              
  Lines        67556    67559       +3     
===========================================
+ Hits         42975    43018      +43     
+ Misses       24581    24541      -40     

Impacted Files	Coverage Δ
...next/accounts/doctype/pricing_rule/pricing_rule.py	71.08% <80.00%> (-0.05%)	⬇️
.../report/delayed_item_report/delayed_item_report.py	60.78% <0.00%> (-35.30%)	⬇️
...urity_shortfall/process_loan_security_shortfall.py	93.75% <0.00%> (-6.25%)	⬇️
...eorder_level/itemwise_recommended_reorder_level.py	88.88% <0.00%> (-3.71%)	⬇️
erpnext/crm/doctype/prospect/prospect.py	56.71% <0.00%> (-1.50%)	⬇️
erpnext/stock/doctype/warehouse/warehouse.py	79.72% <0.00%> (-1.40%)	⬇️
...ctype/accounting_dimension/accounting_dimension.py	65.15% <0.00%> (-0.76%)	⬇️
erpnext/selling/doctype/quotation/quotation.py	54.10% <0.00%> (-0.49%)	⬇️
erpnext/payroll/doctype/salary_slip/salary_slip.py	86.89% <0.00%> (-0.25%)	⬇️
erpnext/selling/doctype/sales_order/sales_order.py	80.47% <0.00%> (ø)
... and 17 more