OAuth Missing redirect URL

### 👟 Reproduction steps Hello all, on a Flutter mobile app with latest Appwrite dependency (25.4.0) I always got "Missing redirect URL" - "Your OAuth login flow is missing a proper redirect URL...." I inspected the url which cause the error, here it is: `https://example.com/console/auth/oauth2/failure?error=%7B"message"%3A"A+user+with+the+same+id%2C+email%2C+or+phone+already+exists+in+this+project."%2C"type"%3A"user_already_exists"%2C"code"%3A409%7D` It seems the app do not handle correctly the error. IMO it's a plugin issue instead of server issue. Note: It works well on freshly created accounts Stack: self hosted 1.9.6 ### 👍 Expected behavior Should close the browser and throw an error "user_already_exists" ### 👎 Actual Behavior It show an Appwrite error <img width="1080" height="2159" alt="Image" src="https://github.com/user-attachments/assets/f3804b34-8666-46c1-9cab-92e8634bae24" /> ### 🎲 Appwrite version Different version (specify in environment) ### 💻 Operating system Linux ### 🧱 Your Environment _No response_ ### 👀 Have you spent some time to check if this issue has been raised before? - [x] I checked and didn't find similar issue ### 🏢 Have you read the Code of Conduct? - [x] I have read the [Code of Conduct](https://github.com/appwrite/.github/blob/main/CODE_OF_CONDUCT.md)