fix(functions): allow forced interactive deletion

[Cedric / ViaDézo1er (viadezo1er)]

• allow --force when selecting a function or scorer interactively
• remove the unnecessary requirement that force mode include a slug

Affects bt scorers/tools/functions delete.

Before:

❯ bt scorers delete -f
error: slug required when using --force. Use: bt scorers delete <slug> --force

After:

❯ bt scorers delete -f
✔ Select scorer · test gemini [slug: test-gemini]
✓ Deleted 'test gemini'
Run `bt scorers list` to see remaining scorers.

[github-actions]

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