[ATOM-15858] Removing unused property from test (#141)

Scripts/AreaLightTest.bv.lua

@@ -20,7 +20,6 @@ function SetupDiskLights()
     SetImguiValue('AreaLightSample/Radius', 1.0)
     SetImguiValue('AreaLightSample/X rotation', -1.5)
     SetImguiValue('AreaLightSample/Y rotation', -0.125)
-    SetImguiValue('AreaLightSample/Emit Both Directions', false)
 end
 
 function SetupCapsuleLights()
@@ -156,4 +155,4 @@ do
     end
 end
 
-OpenSample(nil)
+OpenSample(nil)