nargo fmt should remove unnecessary {} in nested imports

[jfecher]

Aim

See #4529 (comment) for an example which is not caught by the current formatter:

use foo::{
    bar::baz,
    qux::{quux},  // unnecessary but not removed
};

Expected Behavior

The formatter should remove {} on single imports, even if the import is nested

Bug

The formatter does not do so

To Reproduce

Project Impact

None

Impact Context

No response

Workaround

None

Workaround Description

No response

Additional Context

No response

Installation Method

None

Nargo Version

No response

NoirJS Version

No response

Would you like to submit a PR for this Issue?

None

Support Needs

No response