Revert "[ci] Switch to LUCI for Android build-all (#4274)"

[ditman]

This reverts commit 8b6998f.

Attempts to mitigate: flutter/flutter#129467

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[ditman]

We might not be allowed to make bringup: true after the task has been moved out of bringup once :/ I guess the ci.yaml validation will tell!

[ditman]

This was the actual underlying problem:

• [ci] Remove jcenter from legacy project #4306