Avoid assigning QA cards to the main reviewers

[FlorentClarret]

What does this PR do?

Update the trello testable command to:

1. Get the main reviewers of a PR. By main, I pick only the one who approved.
2. Avoid assigning the trello cards to the main reviewers.

Motivation

Ideally, we should not QA a PR we already reviewed.

Additional Notes

Not sure if approvers actually means something. Also, we could update the condition if you think we should not filter on the review status

Review checklist (to be filled by reviewers)

• [ ] Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• [ ] PR title must be written as a CHANGELOG entry (see why)
• [ ] Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• [ ] PR must have changelog/ and integration/ labels attached

[codecov[bot]]

Codecov Report

Merging #12990 (3209960) into master (0b92164) will not change coverage. The diff coverage is n/a.

Flag	Coverage Δ
activemq_xml	82.31% <ø> (ø)
btrfs	82.91% <ø> (ø)
cert_manager	77.41% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

[alopezz]

Any chance of testing this in any way?

[FlorentClarret]

@alopezz I can unit test the call to the github API, I'm going to do that, but for the rest it will need to wait for the refactor