Revert "Icon: use size_hint_min instead of image_size to know the wanted size"

This reverts commit 75176a789981bd6b1ef0bfcc95793c896b5bde07.

Was not the correct solution, as min_size can be smaller than
the real wanted size. Need to find another solution.

Thanks TAsn to spot this

legacy/elementary/src/lib/elm_icon.c

@@ -52,7 +52,7 @@ _icon_size_min_get(Evas_Object *icon)
 {
    int size;
 
-   evas_object_size_hint_min_get(icon, &size, NULL);
+   elm_image_object_size_get(icon, &size, NULL);
 
    return (size < 16) ? 16 : size;
 }