If I have a helm binary on my system path I'd like the tooling to use this instead of download it

[adietish]

Steps:

1. ASSERT: make sure that your plugin did not download the helm binary yet (or remove it from the cache
2. ASSERT: make sure that you have helm installed on your system and that it's available on the system path
3. EXEC: launch plugin

Result: The tooling is downloading the helm binary even though it's already present on the system