[flexiglass] Don't emit from sharedFlowWithState when CANCELED

The attached bug occurs when the state originating from the CANCELED of
LockscreenToPrimaryBouncerTransitionViewModel is received downstream in
DeviceEntryIconViewModel _after_ the correct value from
PrimaryBouncerToLockscreenTransitionViewModel is received. This causes
the alpha of the lock indication view to remain at 0 rather than at 1.

See the long comment in the changed code for more details about why we
should filter out values that come from CANCELED, when Flexiglass is on.

Fix: 379845752
Test: manually verified that the original bug is fixed when Flexiglass
is on
Test: manually verified that swiping completely to Bouncer and returning
to the lockscreen shows the icon, Flexiglass on
Test: unlocked the the device, relocked, and repeated the steps above -
Flexiglass on
Test: manually verified all of the above also when Flexiglass is off
Flag: com.android.systemui.scene_container

Change-Id: I12be2d0a79ecbf89e6282753c8b8c965ac3839fd