[Attenuation][Spatialization] - If speaker output is set to stereo, the Surround 2D Non Spatialized Radius Mode doesn't generate any audio

If Surround 2D is set as the Non Spatialized Radius Mode, there is no fallback option if the user's output is not a surround format (eg stereo). There is also nothing communicated in the Tool Tip.

1) Set your computer output to a stereo configuration 
2) In any project, add a Sound (Sound Wave, MetaSound, etc) to a level as an AmbientSound
3) Select Override Attenuation
4) Under Spatialization, make sure Spatialization is Enabled and set the Non Spatialized Radius Mode to Surround 2D
5) PIE

Expected Result:
 Sound is audible

Actual Result:
 Sound is not audible