Fix not applicable on statement for convert_to_guarded_return

[A4-Tacks]

Fix not applicable in statement when exist else block

Example

fn main() {
    some_statements();
    if$0 let Ok(x) = Err(92) {
        foo(x);
    } else {
        return;
    }
    some_statements();
}

Before this PR

Assist not applicable

After this PR

fn main() {
    some_statements();
    let Ok(x) = Err(92) else {
        return;
    };
    foo(x);
    some_statements();
}