fix(Code): do not show Optimize Code button when no code is available

[ifrost]

✨ Description

Related issue(s):

Fixes #203

📖 Summary of the changes

• line property can be undefined if not available. This way we can check if there are any lines to optimize. Assumption is that we can optimize the code if there's at least one line available.
• Code component has a view model which ensure line is a string and can be displayed.

🧪 How to test?

Check if "Optimize Code" is shown only when there's at least one line available

https://github.com/user-attachments/assets/19c4386b-e0cd-40a5-bc03-c9fcdadf1405

[github-actions[bot]]

Unit test coverage

Lines	Statements	Branches	Functions
	10.64% (415/3897)	8.3% (112/1348)	8.09% (100/1236)