DualCache.async_set_cache and async_set_cache_pipeline were missing the
default_in_memory_ttl injection that the sync set_cache method has. This
caused InMemoryCache to fall back to its own default_ttl (600s) instead
of using DualCache's configured default_in_memory_ttl (typically 60s).
This is particularly impactful for end-user budget enforcement in the
proxy, where cached spend values could remain stale for 10 minutes
instead of 1 minute, allowing users to exceed their budgets.