redirect optional

app/routes.py

@@ -199,7 +199,7 @@ async def post_forderungen_details(
     request: Request,
     primary_key: str,
     source: Annotated[str, Form()],
-    redirect: Annotated[str, Form()],
+    redirect: Annotated[str | None, Form()] = None,
     db: Session = Depends(get_session),
 ):
     pkey = convert_primary_key("forderungen", primary_key)