solved -Issue 16b tilt/pan #5 - EFX in relative mode resets LSB

[GGGss]

While regression testing the 16b engine, QLC+-4.12.8_GIT-20240223-3188c91-16bit-FADE
I came across this issue:

When you start an EFX in relative mode, it resets the LSB values to zero.

Steps to reproduce:
* go into produce
* open DMX monitor
* play with pos 1 / pos2 / pos-preset scenes,
+ Have a look at how nicely the LSB channels are preserved
* Start 'New EFX 8'
+ Watch closely what with starting the EFX it does to the LSB values of the PAN
- It resets them to zero. Issue

New EFX 8 is in relative mode.

https://youtu.be/JgGbwzx7ThU

[GGGss]

With the latest version - this is ~SOLVED~ v4.13.0-20240303-83790
But to be really 'relative', I'll introduce an additional issue report. (Minor - to Major issue involving offsets and width / height of the EFX module)