Ensuring contribution does not process if rewards or a-c is off (0.59)

[ryanml]

Fixes: brave/brave-browser#2804
Resolves brave/brave-browser#2815



Original PR: #1205

[kjozwiak]

@ryanml you'll need to add one of the approvals that's listed under https://github.com/brave/brave-browser/wiki/Triage-Guidelines#uplift-approvers as a reviewer to get this uplifted into 0.59.x:

Current approvers are @rebron @kjozwiak @Sri @bbondy @clifton (Slack usernames)

With the old process, we would search for uplift labels which made it easy to find uplift requests. However, with the new process, if one of the above approvals isn't added as a reviewer, we won't get any emails which will make it hard to find this request.

[kjozwiak]

Uplift to 0.59.x approved after deliberating with @rebron & @bsclifton 👍 Please ensure that all appropriate issues are moved into the correct milestone.