TryFromJs from JsMap for HashMap & BtreeMap

[Nikita-str]

Seems like TryFromJs didn't convert correctly from JsMap into HashMap / BtreeMap

This PR fix it

Example
Next code

use boa_engine::{value::TryFromJs, Context, JsResult, Source};
use std::collections::HashMap;

fn main() -> JsResult<()> {
    let js_code = "new Map([['a', 2], ['b', 3]])";
    let mut context = Context::default();

    let js_value = context.eval(Source::from_bytes(js_code))?;
    println!("{}", js_value.display());

    let map = HashMap::<String, i32>::try_from_js(&js_value, &mut context)?;
    println!("{map:?}");
    Ok(())
}

before this changes will return:

Map { "a" → 2, "b" → 3 }
{}

and after changes returns:

Map { "a" → 2, "b" → 3 }
{"a": 2, "b": 3}

Notes
I don't find more fast way(than the one used in for_each_elem_in_js_map) to get (key, value)'s from JsMap.
Maybe there is a way?
Or maybe I should write it (for example by function like next but that just return Option<(JsValue, JsValue)>)?