[core][ios][osx][android] make SpriteImage accept PremultipliedImage

the SpriteImage constructor signature changes from

SpriteImage(
        uint16_t width, uint16_t height, float pixelRatio,
        std::string&& data, bool sdf = false);

to

SpriteImage(PremultipliedImage&&, float pixelRatio, bool sdf = false)

src/mbgl/annotation/annotation_manager.cpp

@@ -165,7 +165,7 @@ void AnnotationManager::removeIcon(const std::string& name) {
 
 double AnnotationManager::getTopOffsetPixelsForIcon(const std::string& name) {
     auto sprite = spriteStore.getSprite(name);
-    return sprite ? -sprite->height / 2 : 0;
+    return sprite ? -(sprite->image.height / sprite->pixelRatio) / 2 : 0;
 }
 
 } // namespace mbgl