Drop duplicated property filename on AutomaticPlan model

aleksis/apps/chronos/models.py

@@ -1204,11 +1204,6 @@ class AutomaticPlan(LiveDocument):
                 self.current_file.save(self.filename, file_object.file.file)
                 self.save()
 
-    @property
-    def filename(self) -> str:
-        """Get filename (without path) of the PDF file."""
-        return f"{self.slug}.pdf"
-
     class Meta:
         verbose_name = _("Automatic plan")
         verbose_name_plural = _("Automatic plans")