Added support for proxy envs in `litmus` chart

[Jonsy13]

What this PR does / why we need it:

Which issue this PR fixes

(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)

• fixes #322

Special notes for your reviewer:

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• [ ] DCO signed
• [ ] Chart Version bumped
• [ ] Variables are documented in the README.md

[phonkd]

need this

[phonkd]

What is needed to merge this?