Executable Helm method updates the receiver and is not thread safe

We found that a method in the executables.Helm struct is updating the receiver. This is not thread safe, and we should change it:

https://github.com/aws/eks-anywhere/blob/380588591eb2777b3fc8e6d25f315c8b8d12fdcc/pkg/executables/helm.go#L238

Inspect pkg/executables/helm.go around line 238 and trace how the Helm method updates its receiver. Check nearby tests for executable behavior, then verify that concurrent calls no longer share mutable receiver state and run the relevant Go tests.

Written by the indexing model from the issue text.