feat: wait_until method for the wait_queue

[Ddystopia]

For some reason github cannot understand that this is the same branch, so I forced to make the second PR after #1052

Diatomic Waker has a method like this and it is very handy. I've been implementing async wrapper over heapless::mpmc::MpMcQueue and wait_queue is great, but a method like this is really benefitial. You can safely create async versions of enqueue and dequeue, and don't need unsafe to interact with the wait_queue.

Note that this PR has only 1 additional unsafe block.

To give a perspective, this method is used like that :

impl<T, const N: usize> MpMcChannel<T, N> {
    pub const fn new() -> Self {
        Self {
            tx_wait_queue: WaitQueue::new(),
            rx_wait_queue: WaitQueue::new(),
            queue: MpMcQueue::new(),
        }
    }

    pub fn try_send(&self, value: T) -> Result<(), T> {
        while let Some(waker) = self.rx_wait_queue.pop() {
            waker.wake();
        }

        self.queue.enqueue(value)
    }

    pub fn try_recv(&self) -> Option<T> {
        while let Some(waker) = self.rx_wait_queue.pop() {
            waker.wake();
        }

        self.queue.dequeue()
    }

    pub async fn send(&self, value: T) {
        let mut value = Some(value);
        self.tx_wait_queue
            .wait_until(|| {
                self.try_send(value.take().expect("Future is polled after completion"))
                    .map_err(|old_val| value = Some(old_val))
                    .ok()
            })
            .await
    }

    pub async fn recv(&self) -> T {
        self.rx_wait_queue.wait_until(|| self.try_recv()).await
    }
}

[Ddystopia]

@AfoHT #1052 moved there