- Added a new boolean state `isContinuousMode` to the `ChatInputField` widget to handle the continuous mode feature.
- Introduced a new callback function `onContinuousModePressed` to manage the state of the continuous mode from an external source.
- Conditionally rendered the send button based on the `isContinuousMode` state.
- Enhanced the UI by adding a button to toggle between continuous mode and single message mode, which triggers the `onContinuousModePressed` callback.
Added a new state variable `_isContinuousMode` to the ChatViewModel to track whether the chat is in continuous mode or not. This state is toggled via a setter and triggers UI updates through `notifyListeners()`.
Enhanced the `sendChatMessage` method to automatically send a null message if continuous mode is active, triggering the next step in the chat.
Updated the StepRequestBody class to allow both 'input' and 'additionalInput' to be optional. Added logic in toJson() method to return an empty JSON object if both fields are null.
