Fix UnknownModelException

✅ Solution

The "UnknownModelException" often arises from corrupted or missing model files in InvokeAI's models directory or inconsistencies between the configuration file and available models. To resolve this, first, verify the integrity of your model files by re-downloading them, ensuring correct placement in the InvokeAI models directory. Then, refresh the InvokeAI model list using the `invokeai-configure` command, selecting "N" (no custom path) to ensure the standard models path is properly configured.