bbctl - unit tests for util helm client

The code at /util/helm is lacking unit tests.

Option 1: create unit tests for the helm client code (minimum 80% coverage)
Option 2: use upstream go-helm-client library
https://pkg.go.dev/github.com/mittwald/go-helm-client

Notes: How to check test coverage by file

go test -v ./... -coverprofile=cover.txt
go tool cover -html=cover.txt -o cover.html

Then open cover.html file in a browser