`struct_field_align_threshold = 30` doesn't apply when using `use_field_init_shorthand = true`

Formatting incorrectly

I have this code

pub struct Test {
    one:         i32,
    two:         i32,
    three_three: i32,
    four:        i32,
}

impl Test {
    pub fn new(one: i32, bbb: i32, ccccc: i32, ddddd: i32) -> Self {
        Self {
            one:         one,
            two:         bbb,
            three_three: ccccc,
            four:        ddddd,
        }
    }
}

Executing formatting

pub struct Test {
    one:         i32,
    two:         i32,
    three_three: i32,
    four:        i32,
}

impl Test {
    pub fn new(one: i32, bbb: i32, ccccc: i32, ddddd: i32) -> Self {
        Self {
            one,
            two:         bbb,
            three_three: ccccc,
            four:        ddddd,
        }
    }
}

Formatting again

pub struct Test {
    one:         i32,
    two:         i32,
    three_three: i32,
    four:        i32,
}

impl Test {
    pub fn new(one: i32, bbb: i32, ccccc: i32, ddddd: i32) -> Self {
        Self {
            one,
            two: bbb,
            three_three: ccccc,
            four: ddddd,
        }
    }
}

When use_field_init_shorthand is in effect,
the struct_field_align_threshold behaves incorrectly.

Version

rustfmt 1.7.0-nightly (0ecbd06 2024-02-25)

Rustfmt Config

struct_field_align_threshold        = 30
use_field_init_shorthand            = true

Reproduce the issue with the Rust snippet and the two rustfmt settings shown, then run rustfmt and compare both formatting passes. Trace the formatter's handling of struct field alignment and field-init shorthand, and add a regression test if the relevant test location is found. Done means the alignment threshold is respected and repeated formatting is stable.