fix: remove printing errors from IsKubernetesManifest and change doApply to use ParseKubernetesObjects to retrieve the error

[renzodavid9]

Fixes: #8547

Description
skaffold init uses the IsKubernetesManifest to filter the files found in the folder, for each file that is not a K8s manifest skaffold is showing an error, even when this does not represent an error for this command. This PR removes the log from the IsKubernetesManifest function, and change doApply to use ParseKubernetesObjects instead where the error can be returned.

[codecov]

Codecov Report

Merging #8559 (8f1a2b6) into main (290280e) will decrease coverage by 6.29%.
The diff coverage is 54.03%.

@@            Coverage Diff             @@
##             main    #8559      +/-   ##
==========================================
- Coverage   70.48%   64.19%   -6.29%     
==========================================
  Files         515      610      +95     
  Lines       23150    30593    +7443     
==========================================
+ Hits        16317    19640    +3323     
- Misses       5776     9480    +3704     
- Partials     1057     1473     +416     

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/completion.go	13.04% <0.00%> (-1.25%)	⬇️
cmd/skaffold/app/cmd/config/list.go	65.21% <ø> (ø)
cmd/skaffold/app/cmd/config/set.go	88.72% <ø> (ø)
cmd/skaffold/app/cmd/config/util.go	54.28% <ø> (ø)
cmd/skaffold/app/cmd/credits.go	100.00% <ø> (ø)
cmd/skaffold/app/cmd/credits/export.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/deploy.go	40.90% <0.00%> (-12.94%)	⬇️
cmd/skaffold/app/cmd/generate_pipeline.go	60.00% <ø> (ø)
cmd/skaffold/app/cmd/inspect_modules.go	65.00% <ø> (ø)
cmd/skaffold/app/cmd/inspect_profiles.go	66.66% <ø> (ø)
... and 38 more

... and 389 files with indirect coverage changes

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