Apply set_execution_file to specific traces such as forward/backward execution traces

[crcrpar]

With

lightning-thunder/thunder/core/trace.py

Line 671 in 621dce7

def _set_execution_file(path: str) -> None:

, we can modify traces before execution, but it seems that every TraceCtx.python_callable() call gets affected by the function according to

lightning-thunder/thunder/core/trace.py

Lines 495 to 508 in 621dce7

	def python_callable(self, *, global_dicts: None | dict = None, **kwargs: Any) -> Callable:
	python_str: str
	# Writes the program to allow it to be edited before execution
	path: None | str = _get_execution_file()
	if path is not None:
	f = open(path, "w")
	f.write(self.python(**kwargs))
	f.close()
	input(f"Trace written to {os.path.realpath(path)} Press Any key to execute it")
	with open(path) as file:
	python_str = file.read()

.

From my point of view, the number of traces we'd want to modify would be 1 or 2: forward execution trace and/or backward execution trace.
Thus I think it'd be helpful to have an option to only make set_execution_callback_file effective to the two traces mentioned above.