Remove GracefulTimeoutHandling include

What does this MR do and why?

I added this in a previous MR, but it seems like it's overriding a more specific method-level rescue block. 🤷🏼‍♀️ Removing it, since we don't depend on it and it'll simplify things.

The primary problem is that rescue_from and rescue generally play nice with each other, employing a top-to-bottom, right-to-left resolution approach.. but not, apparently, when rescuing the same exception.. or when the rescue_from is included. Since all GracefulTimeoutHandling is giving us here is JSON error handling, and we haven't seen any of those in the trailing 14 days, I'm comfortable removing that and following up with endpoint-specific handling of that format in a follow-up MR next week.