fix(nargo): only search for Nargo.toml in commands which act on a Nargo package

[ax0]

Related issue(s)

Resolves #

Description

This PR fixes the issue where running nargo new unsuccessfully searches for a Nargo.toml file resulting in an error of the following form:

Error: cannot find a Nargo.toml in /tmp

Location:
    crates/nargo/src/cli/mod.rs:67:26

Summary of changes

• Condition added to check command before searching for project root.

Dependency additions / changes

Test additions / changes

Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt with default settings.
• I have linked this PR to the issue(s) that it resolves.
• I have reviewed the changes on GitHub, line by line.
• I have ensured all changes are covered in the description.

Documentation needs

• This PR requires documentation updates when merged.

Additional context

[TomAFrench]

LGTM. Thanks for the fix.