efl/image: remove load_controller events

these aren't implemented by anything and duplicate the functionality provided
by efl.gfx.image::image,preload_state,changed

ref T7876

Reviewed-by: Marcel Hollerbach <mail@marcel-hollerbach.de>
Differential Revision: https://phab.enlightenment.org/D10128

src/lib/efl/interfaces/efl_gfx_image_load_controller.eo

@@ -164,8 +164,4 @@ interface @beta Efl.Gfx.Image_Load_Controller
          }
       }
    }
-   events {
-      load,done: void; [[Emitted after the image has been loaded.]]
-      load,error: Eina.Error; [[Emitted if an error happened during image loading.]]
-   }
 }