feat: add ALLOW_ADMIN_EXPORT to disable exporting of chats and the db

backend/apps/web/routers/utils.py

@@ -91,7 +91,11 @@ async def download_chat_as_pdf(
 
 @router.get("/db/download")
 async def download_db(user=Depends(get_admin_user)):
-
+    if not ALLOW_ADMIN_EXPORT:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail=ERROR_MESSAGES.ACCESS_PROHIBITED,
+        )
     return FileResponse(
         f"{DATA_DIR}/webui.db",
         media_type="application/octet-stream",