[synthetics-job-manager] re-adds inadvertently deleted proxy settings for sjm

[kondracek-nr]

Is this a new chart

No

What this PR does / why we need it:

I inadvertently deleted the proxy settings while working on something else. This PR adds these back so users can run their K8s SJMs behind a proxy.

Which issue this PR fixes

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

• fixes #

Special notes for your reviewer:

Checklist

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

• [x] Chart Version bumped
• [x] Title of the PR starts with chart name (e.g. [mychartname])