Fix crossbario#1892: ignore ty 0.0.53 possibly-missing-submodule + unused-type-ignore-comment

ty is run unpinned (we ride the latest release and adjust the ignore
list as it evolves). ty 0.0.53 began emitting two diagnostic classes on
existing, unchanged source that the check-typing recipe did not ignore,
so `ty check` exited 1 and Code Quality Checks went red:

  - 921x possibly-missing-submodule (vendored FlatBuffers-generated code
    under src/autobahn/wamp/gen/** plus a few flatbuffers.* re-export
    sites in message_fbs.py / message.py / protocol.py)
  -   1x unused-type-ignore-comment (src/autobahn/util.py:1062)

0 errors; all warnings. Drift, not a code regression: master was green
on 2026-06-19 with an earlier ty, and went red on a 2026-06-25 run that
pulled ty 0.0.53 (surfaced on the unrelated example-cleanup PR crossbario#1887).

Add both rules to the check-typing --ignore list. Reproduced red->green
locally with ty 0.0.53 against the cpy311 venv: 922 diagnostics/exit 1
before, "All checks passed!"/exit 0 after.

Note: This work was completed with AI assistance (Claude Code).

Author: oberstet

justfile

@@ -715,6 +715,8 @@ check-typing venv="": (install venv)
         --ignore no-matching-overload \
         --ignore conflicting-declarations \
         --ignore deprecated \
+        --ignore possibly-missing-submodule \
+        --ignore unused-type-ignore-comment \
         src/autobahn/
 
 # pyright --project pyproject-static-typing.toml src/autobahn/wamp/request.py