Fix swallowed CancelledError in start_child_workflow and Nexus operations (Issue #1445)

Author: yegorske50

temporalio/worker/_workflow_instance.py

@@ -2017,6 +2017,7 @@ async def run_child() -> Any:
                 return handle
             except asyncio.CancelledError:
                 apply_child_cancel_error()
+                raise
 
     async def _outbound_start_nexus_operation(
         self, input: StartNexusOperationInput[Any, OutputT]
@@ -2043,6 +2044,7 @@ async def operation_handle_fn() -> OutputT:
                 except asyncio.CancelledError:
                     cancel_command = self._add_command()
                     handle._apply_cancel_command(cancel_command)
+                    raise
 
         handle = _NexusOperationHandle(
             self, self._next_seq("nexus_operation"), input, operation_handle_fn()
@@ -2057,6 +2059,7 @@ async def operation_handle_fn() -> OutputT:
             except asyncio.CancelledError:
                 cancel_command = self._add_command()
                 handle._apply_cancel_command(cancel_command)
+                raise
 
     #### Miscellaneous helpers ####
     # These are in alphabetical order.