fix(samples): use running loop for async input

[Ghraven]

Problem: two async sample input helpers call asyncio.get_event_loop() from inside async functions before scheduling blocking input() calls in an executor. get_event_loop() is deprecated in this usage and can depend on event loop policy behavior.

Before / after: before, the samples asked the policy for an event loop even though a loop is already running. After, they use asyncio.get_running_loop(), preserving the executor behavior while binding to the active loop explicitly.

Verification:

• python -m py_compile python\samples\core_semantic_router_agents.py python\samples\core_async_human_in_the_loop\main.py