move security error handling to use ctx macro

[svix-gabriel]

We recently added a ctx! macro to help make handling and tracing internal server errors much more straightforward. This PR adds ctx! invocations in security.rs to a couple of common errors that were being manually transformed.

This also let us axe the to_internal_server_error function. to_internal_server_error was logging errors, but this was redundant with error::Error's logging in error.rs (when it gets turned into a response for axum).

Motivation

• Cut down boilerplate in security.rs
• Add line tracing information to the internal server errors in security.rs

Solution

• Use the ctx! macro in security.rs
• Implement Traceable for the *Rejection types to make ctx! work