Add better env loading e.g. `nil` from github

[anthony-chaudhary]

Issue

If no variable is set e.g. ABC is not in env, then env loaders like github actions will set it to various values, e.g. nil eg ABC=nil.
Helm, which will error because it doesn't know nil.

Workarounds known so far are:

1. Ensure all variables are added to your values.yaml, eg. if you are using github actions then add these new ones to the env and be sure to set them to none
2. Remove the unused variables from git actions (or your env loader), that will then lean on the helm defaults, which we set to none

Desired state

Helm should do this naturally. If upgrading to v3 doesn't solve it then
we can build some workaround, basically if it's not a recognized value it should default to warning not hard error.

We should fix this in helm since we can't control how values arrive at the values.yaml