Set shimmer corner same as the thumbnail

Signed-off-by: Abdourahamane BOINAIDI <abdourahamane.boinaidi@infomaniak.com>

src/main/res/layout/grid_image.xml

@@ -43,7 +43,7 @@
                 android:layout_margin="@dimen/grid_image_icon_margin"
                 android:contentDescription="@null"
                 android:visibility="gone"
-                app:corners="3"
+                app:corners="6"
                 app:height_weight="0.6"
                 app:width_weight="0.4" />