Fix Debug Handle Map Typing (#363)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/363

The intended typing for PreprocessResult.debug_handle_map was
```
Dict[int, Tuple[int, ...]] || Dict[str, Tuple[int, ...]]
```
Since the delegate identifier can be either a string or int and maps to a Int Tuple of variable length

This fixes the type and gets rid of the pyre ignore

Reviewed By: digantdesai, cccclai

Differential Revision: D49300700

fbshipit-source-id: eaee31eae6d5539d55e9abae418276a6676361a0