Fix fan speed staying high
When fan speed-up time is enabled, layers can inherit a higher fan speed than intended.
If a layer ended with a role-driven fan change, the last applied fan speed
was not properly tracked. As a result, the next layer could start with an
incorrect fan state and keep the higher speed until another fan command
overrode it.
Ensure the emitted fan speed is always tracked correctly, including when
flushing buffered commands at the end of a layer.
Kiss Lorand