Fixed empty message error for computer use

[ehlowe]

Describe the changes you have made:

if the user presses enter without input it will continue and ask again instead of inserting an empty string into the prompt which throws an error

Fixes https://github.com/OpenInterpreter/open-interpreter/issues/1517

Pre-Submission Checklist (optional but appreciated):

• [ ] I have included relevant documentation updates (stored in /docs)
• [x] I have read docs/CONTRIBUTING.md
• [x] I have read docs/ROADMAP.md

OS Tests (optional but appreciated):

• [x] Tested on Windows
• [ ] Tested on MacOS
• [ ] Tested on Linux