Check for pending animations or transitions when scheduling another render pass

In continuous mode, we need to check if there are any pending animations or
transitions so we can properly tell the client application that another render
pass is required.

src/mbgl/map/map_context.cpp

@@ -343,7 +343,7 @@ MapContext::RenderResult MapContext::renderSync(const TransformState& state, con
 
     return RenderResult {
         style->isLoaded(),
-        style->hasTransitions()
+        style->hasTransitions() || painter->needsAnimation()
     };
 }