Heap dumps should be deleted once they've been captured

[jamescrosswell]

So yeah, we know where the dump file is and could just let people know the location where it's been stored, if it's too big to add as an attachment. I imagine a lot of folks wouldn't have access to it in a production environment though.

But if we're doing this now we need to keep track and delete old files etc to avoid a disk filling up.
If we're not sending to Sentry, I would delete the dump file and log diag logger error about it.

If Sentry increases the size limit one would need to bump the SDK (and we'd need to amend the SDK limits though)

Originally posted by @bruno-garcia in #4007