I2SOut: Enable ticks during audio playback
I2SOut: Enable ticks during audio playback

.. otherwise, the background callback to load the I2S fifos does not get
run.  (I'm not sure this is _correct_ behavior of sleep + background
tasks, but it is the current behavior)

adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython