fix: Misc enhancements

[gavindsouza]

Changes

• Check for merge conflicts in repo before dependency setup in the CI pipeline [better failfast]
• Use assertSequenceEqual for resilient tests (that are dependent on frappe.db.sql retval)
• perf: Remove unnecessary query for GlobalDefaults.current_fiscal_year being None

Changes inspired by MariaDB client switch in frappe/frappe#16961

[codecov]

Codecov Report

Merging #31454 (3c26415) into develop (9439a7f) will increase coverage by 0.10%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop   #31454      +/-   ##
===========================================
+ Coverage    63.31%   63.41%   +0.10%     
===========================================
  Files          813      813              
  Lines        57507    57507              
===========================================
+ Hits         36409    36469      +60     
+ Misses       21098    21038      -60     

Impacted Files	Coverage Δ
...t/setup/doctype/global_defaults/global_defaults.py	97.43% <100.00%> (ø)
...eport/item_variant_details/item_variant_details.py	31.32% <0.00%> (-53.02%)	⬇️
...rial_no_valuation/incorrect_serial_no_valuation.py	85.96% <0.00%> (-10.53%)	⬇️
...rpnext/accounts/doctype/shareholder/shareholder.py	80.00% <0.00%> (-10.00%)	⬇️
...t/accounts/report/sales_register/sales_register.py	73.68% <0.00%> (-8.19%)	⬇️
...e/asset_value_adjustment/asset_value_adjustment.py	87.95% <0.00%> (-3.62%)	⬇️
.../report/bom_operations_time/bom_operations_time.py	89.13% <0.00%> (-2.18%)	⬇️
erpnext/stock/reorder_item.py	73.33% <0.00%> (-1.67%)	⬇️
...em_wise_sales_register/item_wise_sales_register.py	60.90% <0.00%> (-1.37%)	⬇️
erpnext/stock/report/stock_ageing/stock_ageing.py	93.75% <0.00%> (-0.97%)	⬇️
... and 28 more