fix: no deref index-expr for extract_function

[A4-Tacks]

Fixes #22023

Example

fn foo() {
    let mut arr = [1i32];
    $0arr[0] = 3;$0
    let _ = arr;
}

Before this PR

fn foo() {
    let mut arr = [1i32];
    fun_name(&mut arr);
    let _ = arr;
}

fn $0fun_name(arr: &mut [i32; 1]) {
    *arr[0] = 3;
}

After this PR

fn foo() {
    let mut arr = [1i32];
    fun_name(&mut arr);
    let _ = arr;
}

fn $0fun_name(arr: &mut [i32; 1]) {
    arr[0] = 3;
}