Discard awaitable result with explicit underscore in resiliency interceptor

CodeQL's `py/ineffectual-statement` heuristic re-flagged `await result` in
`AsyncClientResiliencyInterceptor._record_outcome` after the previous fix:
the rule treats expression statements whose value is discarded as unused, and
does not recognise that `await` is always a side-effecting suspension point
(the whole purpose of the call is to run the async recreate callback to
completion).

Rewriting the line as `_ = await result` keeps the exact same runtime
behaviour but documents the intent (return value intentionally discarded) and
satisfies the linter.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Bernd Verst

durabletask/internal/grpc_resiliency.py

@@ -149,6 +149,9 @@ async def _record_outcome(self, method: str, error: Optional[BaseException]) ->
             if self._failure_tracker.record_failure():
                 result = self._on_recreate()
                 if inspect.isawaitable(result):
-                    await result
+                    # ``_ =`` signals that we await purely for the side effect
+                    # of running the recreate callback to completion; the
+                    # awaitable's return value is intentionally discarded.
+                    _ = await result
         else:
             self._failure_tracker.record_success()