Enhance event loop handling in Event class and utility functions

[gnzsnz]

address #8

• Added check to prevent running Event.run() within an already running asyncio event loop.
• Implemented cleanup of pending tasks after running the event list.
• Updated get_event_loop() to handle different scenarios for retrieving the asyncio event loop.

[gnzsnz]

py314 is working fine with this fix.

https://github.com/ib-api-reloaded/eventkit/actions/runs/21177052468/job/60909715662?pr=9#step:8:111

Please note that, now we get the deprecation warning with get_event_loop_policy, but not with asyncio.get_event_loop() so the (knock on good) way forward should be to use asyncio.get_event_loop().

dev/eventkit/eventkit/util.py:27: DeprecationWarning: 'asyncio.get_event_loop_policy' is deprecated and slated for removal in Python 3.16
    return asyncio.get_event_loop_policy().get_event_loop()