ZulipMobile: Add and use RootErrorBoundary.

[chrisbobbe]

Fixes: #4584

[chrisbobbe]

See screenshots/discussion at #4584 (comment).

[chrisbobbe]

Hmm, potentially interesting: Sentry provides a ready-to-use component Sentry.ErrorBoundary. It looks like it was designed for use on the web, so in particular its built-in user feedback widget hasn't been working for me.

But other than that, I think it'd work, if we wanted to use it. One nice thing, if I pass a function for the fallback prop, I get the error info, as I'd expect (we'd use that to show the stack trace, like we do in this revision)— but I also get the Sentry event ID, which could be useful debugging data.

[chrisbobbe]

It looks like it was designed for use on the web, so in particular its built-in user feedback widget hasn't been working for me.

Though it looks like it might not be too hard to set something like this up manually: getsentry/sentry-react-native#500

[gnprice]

Looks good, thanks! Merging.

I have one bit of UI feedback that I think is worth doing (naturally we don't want to spend a lot of time on this UI): instead of having a lot of text in the button:

a more idiomatic thing to do would be to have some text to say most of that, and then have the button very concisely say what the button itself will do. Like maybe "Copy details". See e.g.:
https://material.io/components/buttons#text-button

But given that I'd like to ship a beta today with #4588, and it'd be good to include this in that too, that is not something worth blocking on and instead can be a small followup 🙂

[gnprice]

(Also I made a tiny formatting tweak to the output:

 Component Stack:
-
 ${

because it seemed like empirically there were one too many blank lines in there. My screenshot just above reflects that change.)

[chrisbobbe]

Thanks for the review!