Add File Existence Check and Confirmation Prompt to createFigmadocFromUrl Function

[lucksy]

The function now checks if a target file already exists and prompts the user for confirmation before overwriting it. This update prevents accidental data loss and gives users more control over file operations.

[ptomas-figma]

Thank you for your interest in contributing to Code Connect. We'll consider adding the proposed changes to the project, but we're not ready to merge external contributions yet. For further discussion about new features or ideas, please use the Issues tab on this repo.