fix __file__ value inside components

Summary:
Currently when we exec a component, we pass it the caller file's namespace. As a result, `__file__` resolves to `.../torchx/specs/finder.py` inside the compoennt at runtime, which is confusing.
This fixes that.

Differential Revision: D73793210

Author: Daniel Ohayon

torchx/specs/finder.py

@@ -282,6 +282,8 @@ def find(
 
         file_source = read_conf_file(self._filepath)
         namespace = globals()
+        # so that __file__ used inside the component points to the correct file
+        namespace["__file__"] = self._filepath
         exec(file_source, namespace)  # noqa: P204
         if self._function_name not in namespace:
             raise ComponentNotFoundException(