Fix 3812; Error message changed and check for MalformedYamlError

[m-Bilal]

Fixes #3812

I have created a new Error type MalformedYamlError and introduced a check for it at:

kustomize/api/internal/target/kusttarget.go

Lines 407 to 412 in c65ef48

	if errF := kt.accumulateFile(ra, path); errF != nil {
	// not much we can do if the error is an HTTP error so we bail out
	if errors.Is(errF, load.ErrorHTTP) {
	return nil, errF
	}
	ldr, err := kt.ldr.New(path)

If the check is successful, return so that Kustomize does not try to load the file as a directory.

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @m-Bilal. Thanks for your PR.

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[natasha41575]

/ok-to-test

Thank you for working on this!

[m-Bilal]

I think this would also partially fix #4348

[natasha41575]

Looks great! Very minor comment, I'd like to have the test compare the full actual error string.

[natasha41575]

Please also add a check for the error contents, e.g. assert.Equal(t, err.Error(), expectedErr)

[natasha41575]

This is so much better, thank you!

[natasha41575]

/lgtm
/approve

[natasha41575]

Merging so it can be part of today's release