feat(function-calling): Enable concurrent function calls

[atacan]

handle_function_calls_async and related functions were modified to support concurrent execution of function calls, specifically by leveraging asyncio.create_task

Introduced a new test script test_concurrent_functions.py and "sample" code to check whether the tools are run concurrently.

Using "sleep" in tests might not be a good idea, though.

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[ryanaiagent]

Hi @atacan and thanks to everyone who participated in this thread.

We're currently doing some housekeeping on our pull request queue. Given the rapid pace of development and the number of updates since this was last active, there's a good chance this pull request needs to be caught up to the latest version. To help us keep our backlog focused on current pull requests, we are closing this as stale.

If you're still interested in contributing to this change, could you please update to the very latest version of the library and create a new pull request? Our team will be glad to help with the refreshed PRs and answer any questions!

Thanks for your contribution and understanding!