feat: ajouter le tri des activités dans l'admin par date de modification

lemarche/siaes/admin.py

@@ -735,7 +735,7 @@ def logs_display(self, siaeuserrequest=None):
 
 @admin.register(SiaeActivity, site=admin_site)
 class SiaeActivityAdmin(admin.ModelAdmin):
-    list_display = ["id", "siae_with_link", "sector_group", "created_at"]
+    list_display = ["id", "siae_with_link", "sector_group", "created_at", "updated_at"]
     list_filter = ["sectors"]
     search_fields = ["id", "siae__id", "siae__name"]
     search_help_text = "Cherche sur les champs : ID, Structure (ID, Nom)"