Revert "[device_settings] Use fuchsia.update.ChannelControl."

This reverts commit 98f164e9c75be853566d5c3491afe9c528a691f6.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> [device_settings] Use fuchsia.update.ChannelControl.
> 
> Bug: 37233
> Test: fx run-host-tests device_settings_tests
> 
> Change-Id: Ia050d51a38d7234f59fc016c09b8e67c7cbd5d53

TBR=ejia@google.com,etryzelaar@google.com,aaronwood@google.com,senj@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 37233
Change-Id: I2d3fca9b8c266f19c5c8ccc0adac49432631743b
5 files changed
tree: ad27b3c87d030ea263c120649cde25af4d71745f
  1. src/