image/rendering: Do not config adj in snapshot

This caused warnings and scrollbars to disappear under certain
conditions.

src/widgets/image/loading.rs

@@ -117,6 +117,7 @@ impl LpImage {
                 self.notify_image_size_available();
                 self.configure_best_fit();
                 self.request_tiles();
+                self.configure_adjustments();
             }
             DecoderUpdate::Redraw => {
                 self.set_loaded(true);

src/widgets/image/rendering.rs

@@ -63,9 +63,6 @@ impl WidgetImpl for imp::LpImage {
         let display_width = obj.image_displayed_width();
         let display_height = obj.image_displayed_height();
 
-        // make sure the scrollbars are correct
-        obj.configure_adjustments();
-
         let applicable_zoom = obj.applicable_zoom();
 
         let scaling_filter = if obj.metadata().format().map_or(false, |x| x.is_svg()) {

src/widgets/image/zoom.rs

@@ -72,6 +72,7 @@ impl LpImage {
             self.imp().zoom.set(best_fit_level);
             self.set_zoom_target(best_fit_level);
             self.zoom_animation().pause();
+            self.configure_adjustments();
         }
     }