Remove an assert referencing checkLightId, which seems not to exist anywhere

[daleglass]

This one is confusing me greatly.

It's a line from 8 years ago, and apparently this hasn't been blowing up for anyone else?

/home/dale/git/overte/overte/libraries/render-utils/src/LightStage.cpp: In member function ‘void LightStage::updateLightArrayBuffer(render::Stage::Index)’:
/home/dale/git/overte/overte/libraries/render-utils/src/LightStage.cpp:392:12: error: ‘checkLightId’ was not declared in this scope
  392 |     assert(checkLightId(lightId));
      |            ^~~~~~~~~~~~

There appear to be no references to this function in the source.

[HifiExperiments]

oh I accidentally removed this in #1177 but only compiled in release mode, sorry

[daleglass]

that’s fun…is it being compiled out?

No, the function just seems to be completely missing from the source