fix: don't send error in skaffoldLogEvent if error is nil

[MarlonGamez]

Fixes: #6747

Description
This PR updated the function used to send our error message through the event stream. It now should not be sending a final error message if the error is nil

[codecov]

Codecov Report

Merging #6945 (0ddf78b) into main (290280e) will decrease coverage by 1.66%.
The diff coverage is 56.70%.

@@            Coverage Diff             @@
##             main    #6945      +/-   ##
==========================================
- Coverage   70.48%   68.81%   -1.67%     
==========================================
  Files         515      551      +36     
  Lines       23150    25267    +2117     
==========================================
+ Hits        16317    17388    +1071     
- Misses       5776     6710     +934     
- Partials     1057     1169     +112     

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/deploy.go	52.00% <ø> (-1.85%)	⬇️
cmd/skaffold/app/cmd/dev.go	84.61% <0.00%> (ø)
cmd/skaffold/app/cmd/render.go	36.66% <0.00%> (-4.72%)	⬇️
cmd/skaffold/skaffold.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/inspect_tests.go	62.50% <14.28%> (-1.14%)	⬇️
cmd/skaffold/app/cmd/lsp.go	28.12% <28.12%> (ø)
cmd/skaffold/app/cmd/fix.go	68.85% <40.00%> (-7.62%)	⬇️
cmd/skaffold/app/cmd/lint.go	42.85% <42.85%> (ø)
cmd/skaffold/app/cmd/find_configs.go	48.88% <50.00%> (+0.24%)	⬆️
cmd/skaffold/app/skaffold.go	76.19% <70.00%> (-8.43%)	⬇️
... and 169 more

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