Revert "Add -vvv briefcase logging in debug-mode CI reruns (#221)"

[freakboy3742]

Reverts #392

This had an unexpected side effect; the change passes in CI, but causes issues when the workflow is used by an external project:

Invalid workflow file: .github/workflows/ci.yml#L31
error parsing called workflow
".github/workflows/ci.yml"
-> "beeware/.github/.github/workflows/app-build-verify.yml@main" (source branch with sha:5e182e3887ea6079df0e724bb9e18c21dab91ce9)
: (Line: 76, Col: 28): Unrecognized named-value: 'runner'. Located at position 1 within expression: runner.debug == '1' && '-vvv' || ''