[BUG]: Infinite loading when no input is provided

### Bug Description

On the Text Input page, clicking Next without providing any input (text or Google Doc URL) causes the loading spinner to remain active forever.

This happens because the handleSaveToLocalStorage function does not handle the case where both docUrl and text are empty, leaving the component stuck in a loading state.

### Steps to Reproduce

1. Click on Let's Get Started
2. Choose any one of the 4 options (i.e. Short-Answer Type Questions or Multiple Choice Questions or True/False Questions or All Questions)
3. Click on Fire Up
4. Without uploading anything or typing anything in Enter Google Doc URL text area, simply click on Next button.

### Logs and Screenshots

Image of the infinite loop

### Environment Details

_No response_

### Impact

Low - Minor inconvenience

### Code of Conduct

- [x] I have joined the [Discord server](https://discord.gg/hjUhu33uAn) and will post updates there
- [x] I have searched existing issues to avoid duplicates