Moved ambient lights out of SkLight's light array

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2287553002

Committed: https://skia.googlesource.com/skia/+/8f98f0aa2d3f7571a890b916c7c4b5ee831e9686
Review-Url: https://codereview.chromium.org/2287553002
diff --git a/samplecode/SampleBevel.cpp b/samplecode/SampleBevel.cpp
index e592cf1..cbeb249 100644
--- a/samplecode/SampleBevel.cpp
+++ b/samplecode/SampleBevel.cpp
@@ -749,7 +749,7 @@
                                                                         fLightDefs[i].fDirXY.fY,
                                                                         fLightDefs[i].fDirZ)));
         }
-        builder.add(SkLights::Light::MakeAmbient(SkColor3f::Make(0.4f, 0.4f, 0.4f)));
+        builder.setAmbientLightColor(SkColor3f::Make(0.4f, 0.4f, 0.4f));
         fLights = builder.finish();
 
         // Draw shapes