Use InterruptExecutor in examples

[Dicklessgreat]

From https://github.com/Dicklessgreat/daisy_embassy/pull/10#issuecomment-2268528418

The recorder example stuck because of the problems with the SD card implementation, so let's just try the InterruptExecutor with looper example here.

[Dicklessgreat]

Current error: looper.rs line 104

defmt::unwrap!(spawner.spawn(join(interface.start(), audio_callback_fut)));

mismatched types
expected struct `embassy_executor::SpawnToken<_>`
   found struct `embassy_futures::join::Join<impl core::future::Future<Output = !>, {async block@examples/looper.rs:56:30: 92:6}>`

One solution is to create an embassy_executor::task function that takes Interface as an argument, but it fails because the ZeroCopy field in Interface prevent to Send it to the task. Therefore, the audio callback mechanism must be re-implement.

[Dicklessgreat]

Now I added impl FnMut(&[u32], &mut [u32]) as an argument to the Interface::start(). So we can start audio callback like:

interface
    .start(|input, output| {
        output.copy_from_slice(input);
    })
    .await;

(from passthrough example)

All examples works fine.

@kalkyl How do you think this audio callback interfaces? Another idea I have is to make methods like fn get_stereo(&mut self, buffer: &mut [u32]) and fn set_stereo(&mut self, buffer: &[u32]) in Interface.

[Dicklessgreat]

I merged this pull request as I want to move on to the next changes, but if anyone has any ideas regarding the audio callback, please feel free to comment here at any time. I'd love to hear your thoughts.