Transition times on LED1923R5 and LED1924G9 are off by one

Hey there,

I'm trying to get this sorted since beginning of the year but it seems the bug in the handling of transition times is in the firmware of my bulbs and not in the zigbee2mqtt bridge.

As I mentioned in this and this issue at zigbee2mqtt, setting zero transition times in order to get proper colorful signaling effects the effect time actually results in being one second long.

It is not possible to set a negative transition time so I'm currently stuck with 1 second of transition, which especially bugs me on the LED1923R5 (firmware 1.0.021) as the non-rgb variant LED2005R5/LED2106R3 (firmware 3.0.10) does properly set the transition to 0 when set to 0.

I hoped to to get this sorted now with the support of IKEA or the community here. Thanks in advance!