update exit code to 0 if patch not needed

[juanvallejo]

Release note:

The `kubectl patch` command no longer exits with exit code 1 when a redundant patch results in a no-op

The specific logic in the patch command that exited with code 1, was only doing so when there was no diff between an existing object and its patched counterpart. (In case of errors, we just return those, which eventually ends up exiting with code 1 anyway). This patch removes this block, as we should not be treating patch no-ops as errors.

Fixes #58212

cc @soltysh

[neolit123]

/sig cli

[soltysh]

Can you please add a tests verifying:

1. that exit code is 0, when the patch was empty
2. that exit code is non-zero, when the patch command actually failed

[juanvallejo]

@soltysh Added a test. Although I realize after adding it, that only semantic or type errors will result in the error being printed out and an exit code of 1. If someone were to, for example, update an immutable field on a pod, or set a value for a non-existent spec field on a pod (like replicas), the server would just return the old object with no error, and the command would exit with the message "not patched" (as before), but with exit code 0 (since the old and new object were the same)

[soltysh]

That's reasonable.

[soltysh]

/approve

Please squash your changes into single commit and I push this forward.

[neolit123]

/test pull-kubernetes-integration

[soltysh]

/lgtm

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