Add auto_stop flag check on backend for confirmation dialog.

[keevindoherty]

Summary

Companion to opencap-org/opencap-viewer#534

This PR adds the auto_stop parameter used in opencap-org/opencap-viewer#534 to allow a user to abort neutral pose processing.

It's worth noting this is kind of a hack. Here we simply won't stop recording until a user moves through the confirmation dialog. I think what you'd probably prefer is to stop the recording after 2 seconds in any case, and simply not proceed with processing that data.

cc: @ashcollimore

Testing

I didn't have a straightforward way to quickly test this locally, but I'm happy to take suggestions if you'd prefer I test this on my end.

[keevindoherty]

I think what you'd probably prefer is to stop the recording after 2 seconds in any case, and simply not proceed with processing that data.

I'll take a quick pass at trying to fix this later today or tomorrow before it's ready for review.