chore: remove unuse untar option

[Abirdcfly]

What this PR does / why we need it:
getter.options has parameters untar and its setting function WithUntar().
But it's not used anywhere, not even in the tests.
Special notes for your reviewer:

If applicable:

• this PR contains documentation
• this PR contains unit tests
• this PR has been tested for backwards compatibility

[mattfarina]

Helm follows semantic versioning. We cannot remove this until Helm v4 or the Go API will be broken.

A useful change would be to have a code comment noting that it's deprecated.

[Abirdcfly]

We cannot remove this until Helm v4 or the Go API will be broken.

But options.untar is an Non-capitalized identifier. it can not be exported and can only be accessed from within the same package, and we do not use this identifier in options package...

So, neither options.untar nor WithUntar() will have any effect.

[mattfarina]

@Abirdcfly The issue is with WithUntar. That is a public method that could be used in some calling code for someone using the Helm SDK. Even if it does nothing. Removing it will break their calling code. This is part of the public Helm Go SDK API so we can't remove it until Helm v4. To remove it would violate Semantic Versioning.

[joejulian]

Thanks for noticing this and making an effort, @Abirdcfly . I'm going to go ahead and close this, though, since it's not something that can be merged.