ci: comment about coverage after min. 3 builds

[ankush]

• Codecov is prematurely commenting with wrong/misleading coverage information.
• Comment only after 3 build results are received.

[codecov]

Codecov Report

Merging #27544 (0f20b0c) into develop (e6a1ad8) will increase coverage by 0.04%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop   #27544      +/-   ##
===========================================
+ Coverage    54.48%   54.53%   +0.04%     
===========================================
  Files         1333     1333              
  Lines        70696    70698       +2     
===========================================
+ Hits         38520    38555      +35     
+ Misses       32176    32143      -33     

Impacted Files	Coverage Δ
erpnext/stock/stock_ledger.py	85.40% <0.00%> (-1.45%)	⬇️
erpnext/portal/utils.py	30.00% <0.00%> (-1.43%)	⬇️
erpnext/stock/reorder_item.py	75.22% <0.00%> (-0.89%)	⬇️
...ice_creation_tool/opening_invoice_creation_tool.py	60.41% <0.00%> (-0.70%)	⬇️
erpnext/hr/utils.py	72.80% <0.00%> (-0.44%)	⬇️
...ctype/stock_reconciliation/stock_reconciliation.py	82.85% <0.00%> (-0.43%)	⬇️
...cturing/doctype/production_plan/production_plan.py	69.78% <0.00%> (-0.06%)	⬇️
...ext/payroll/doctype/payroll_entry/payroll_entry.py	70.86% <0.00%> (ø)
erpnext/accounts/utils.py	59.70% <0.00%> (+0.18%)	⬆️
...stock/doctype/purchase_receipt/purchase_receipt.py	90.61% <0.00%> (+0.26%)	⬆️
... and 12 more