PDS: Panic when making calls to com.atproto.server.refreshSession

[rudyfraser]

Panicking during refresh session calls. Issue seems to stem from datetime parsing:

POST /xrpc/com.atproto.server.refreshSession? application/json:
   >> Matched: (refresh_session) POST /xrpc/com.atproto.server.refreshSession
 thread 'rocket-worker-thread' panicked at /usr/local/cargo/registry/src/index.crates.io-6f17d22bba15001f/chrono-0.4.26/src/naive/datetime/mod.rs:122:18:
 invalid or out-of-range datetime
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
   >> Handler refresh_session panicked.
    >> This is an application bug.
    >> A panic in Rust must be treated as an exceptional event.
    >> Panicking is not a suitable error handling mechanism.
    >> Unwinding, the result of a panic, is an expensive operation.
    >> Panics will degrade application performance.
    >> Instead of panicking, return `Option` and/or `Result`.
    >> Values of either type can be returned directly from handlers.
    >> A panic is treated as an internal server error.
    >> Outcome: Error(500 Internal Server Error)
    >> Responding with registered (default_catcher) default catcher.