fix: keyerror on gl and pl comparision report

[ruthra-kumar]

Traceback (most recent call last):
File "apps/frappe/frappe/core/doctype/prepared_report/prepared_report.py", line 79, in generate_report
result = generate_report_result(report=report, filters=instance.filters, user=instance.owner)
File "apps/frappe/frappe/__init__.py", line 802, in wrapper_fn
retval = fn(*args, **get_newargs(fn, kwargs))
File "apps/frappe/frappe/desk/query_report.py", line 89, in generate_report_result
res = get_report_result(report, filters) or []
File "apps/frappe/frappe/desk/query_report.py", line 70, in get_report_result
res = report.execute_script_report(filters)
File "apps/frappe/frappe/core/doctype/report/report.py", line 131, in execute_script_report
res = self.execute_module(filters)
File "apps/frappe/frappe/core/doctype/report/report.py", line 148, in execute_module
return frappe.get_attr(method_name)(frappe._dict(filters))
File "apps/erpnext/erpnext/accounts/report/general_and_payment_ledger_comparison/general_and_payment_ledger_comparison.py", line 219, in execute
columns, data = rpt.run()
File "apps/erpnext/erpnext/accounts/report/general_and_payment_ledger_comparison/general_and_payment_ledger_comparison.py", line 208, in run
self.compare()
File "apps/erpnext/erpnext/accounts/report/general_and_payment_ledger_comparison/general_and_payment_ledger_comparison.py", line 144, in compare
self.diff[(x[0], x[1], x[2], x[3])].update(frappe._dict({"pl_balance": x[4]}))