Build CI

Implement `audiomixer.MixerVoice.level` as `synthio.BlockInput` #15847

Annotations

10 errors

Build microbit_v2 for en_US took 50.96s and failed

Build microbit_v2 for de_DE took 18.15s and failed

Build microbit_v2 for en_GB took 16.65s and failed

Build microbit_v2 for en_x_pirate took 16.53s and failed

Build microbit_v2 for es took 16.31s and failed

Build microbit_v2 for fil took 17.03s and failed

Build microbit_v2 for fr took 17.82s and failed

Build microbit_v2 for ID took 17.08s and failed

Build microbit_v2 for it_IT took 17.14s and failed

Build microbit_v2 for ja took 15.59s and failed