Fix media layout with unknown sizes

mastodon/src/main/java/org/joinmastodon/android/ui/drawables/BlurhashCrossfadeDrawable.java

@@ -99,11 +99,15 @@ public class BlurhashCrossfadeDrawable extends Drawable{
 
 	@Override
 	public int getIntrinsicWidth(){
+		if(width==0)
+			return imageDrawable==null ? 1920 : imageDrawable.getIntrinsicWidth();
 		return width;
 	}
 
 	@Override
 	public int getIntrinsicHeight(){
+		if(height==0)
+			return imageDrawable==null ? 1080 : imageDrawable.getIntrinsicHeight();
 		return height;
 	}