[Bug Report] Apex3 TKL flickers when changing brightness values

Description of Bug

With the Apex3 TKL-keyboard connected, open the OpenRGB client, then select the keyboard:

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Then attempt to change the brightness slider.

Result: Flickering keyboard. See video:

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Also sometimes (hard to reproduce): Segfault.

Attached Log (Analysis)

I debugged the code with a debugger and traced the problem to these lines

https://gitlab.com/CalcProgrammer1/OpenRGB/-/blob/master/Controllers/SteelSeriesController/RGBController_SteelSeriesApex3.cpp#L103

and

https://gitlab.com/CalcProgrammer1/OpenRGB/-/blob/master/Controllers/SteelSeriesController/RGBController_SteelSeriesApex3.cpp#L117-125

It seems that modes[active_mode].colors is not initialized (modes[active_mode].colors.size() == 0) while this->colors.size() == 8 (correct for the Apex3 TKL). I do not know what the difference between those two value lists are tbh, but the lines also seem inconsistent with one sourcing another value list than the other.

Operating System

Linux... I will cut it short, because I think that I know what the error is and have a suggested fix that needs to be reviewed though.

Hardware Configuration

(leaving out because issue seems to be islated to the Apex3 TKL and patch is ready)