Fix `encoder_queue_full_advanced()` for non-power-of-2 queue sizes
`(events->tail - 1) % MAX_QUEUED_ENCODER_EVENTS` did not calculate what
the rest of code expected when `events->tail` was 0, except when
`MAX_QUEUED_ENCODER_EVENTS` happened to be a power of 2, so the code
seemed to work when the number of encoders was less than 4 (in that case
`MAX_QUEUED_ENCODER_EVENTS` was set to 4), but broke when the number of
encoders was 4 or more. Fix the queue full check to avoid negative
numbers in calculations.