fix issue 3425 do not default to turntable when z is zero

Author: archmoj

src/plots/gl3d/layout/defaults.js

@@ -128,9 +128,9 @@ function handleGl3dDefaults(sceneLayoutIn, sceneLayoutOut, coerce, opts) {
                 var y = sceneLayoutIn.camera.up.y;
                 var z = sceneLayoutIn.camera.up.z;
 
-                if(!x || !y || !z) {
+                if((!x && x !== 0) || (!y && y !== 0) || (!z && z !== 0)) {
                     dragmode = 'turntable';
-                } else if(z / Math.sqrt(x * x + y * y + z * z) > 0.999) {
+                } else if(z !== 0 && z / Math.sqrt(x * x + y * y + z * z) > 0.999) {
                     dragmode = 'turntable';
                 }
             } else {