Revert "[ios] Fixed auto-shrinking annotation views"

This reverts commit 0d7d244.

platform/ios/src/MGLAnnotationView.mm

@@ -116,7 +116,7 @@ - (void)updateTransform
         // reduction is then normalized for a scale of 1.0.
         CGFloat pitchAdjustedScale = 1.0 - maxScaleReduction * pitchIntensity;
 
-        CATransform3D transform = CATransform3DIdentity;
+        CATransform3D transform = self.layer.transform;
         self.layer.transform = CATransform3DScale(transform, pitchAdjustedScale, pitchAdjustedScale, 1);
     }
 }