fix: 🐛 Fix remove task functionality on _execute_task, specially when the task has gone missing

[upchunk]

Fix The following Issues:

Exception in callback WorkflowBroker._execute_task.<locals>.<lambda>() at C:\Users\habi6799\Desktop\PROJECT\ai-workflow\.venv\Lib\site-packages\workflows\runtime\broker.py:108
handle: <Handle WorkflowBroker._execute_task.<locals>.<lambda>() at C:\Users\habi6799\Desktop\PROJECT\ai-workflow\.venv\Lib\site-packages\workflows\runtime\broker.py:108>
Traceback (most recent call last):
  File "C:\Users\habi6799\AppData\Local\Python\pythoncore-3.13-64\Lib\asyncio\events.py", line 89, in _run
    self._context.run(self._callback, *self._args)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\habi6799\Desktop\PROJECT\ai-workflow\.venv\Lib\site-packages\workflows\runtime\broker.py", line 108, in <lambda>
    task.add_done_callback(lambda _: self._workers.remove(task))
                                     ~~~~~~~~~~~~~~~~~~~~^^^^^^
ValueError: list.remove(x): x not in list
Exception in callback Dispatcher.span.<locals>.wrapper.<locals>.handle_future_result()() at C:\Users\habi6799\Desktop\PROJECT\ai-workflow\.venv\Lib\site-packages\llama_index_instrumentation\dispatcher.py:300
handle: <Handle Dispatcher.span.<locals>.wrapper.<locals>.handle_future_result()() at C:\Users\habi6799\Desktop\PROJECT\ai-workflow\.venv\Lib\site-packages\llama_index_instrumentation\dispatcher.py:300>  
Traceback (most recent call last):
  File "C:\Users\habi6799\AppData\Local\Python\pythoncore-3.13-64\Lib\asyncio\events.py", line 89, in _run
    self._context.run(self._callback, *self._args)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\habi6799\Desktop\PROJECT\ai-workflow\.venv\Lib\site-packages\llama_index_instrumentation\dispatcher.py", line 308, in handle_future_result
    result = None if future.exception() else future.result()
                     ~~~~~~~~~~~~~~~~^^
asyncio.exceptions.CancelledError

[adrianlyjak]

@upchunk Thanks!

[coveralls]

Pull Request Test Coverage Report for Build 19329265157

Details

• 8 of 8 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 89.653%

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Totals
Change from base Build 19172109139:	0.02%
Covered Lines:	2686
Relevant Lines:	2996

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💛 - Coveralls