Fix type checking errors in resolver directory

[neubig]

This PR fixes type checking errors in the openhands/resolver directory by:

1. Adding type hints to the parse_git_binary_diff function in openhands/resolver/patching/patch.py
2. Fixing the type checking error by properly handling the case where the input is a string vs a list of strings

The changes ensure that all mypy type checking errors in the resolver directory are resolved.

---

To run this PR locally, use the following command:

docker run -it --rm   -p 3000:3000   -v /var/run/docker.sock:/var/run/docker.sock   --add-host host.docker.internal:host-gateway   -e SANDBOX_RUNTIME_CONTAINER_IMAGE=docker.all-hands.dev/all-hands-ai/runtime:c00aa10-nikolaik   --name openhands-app-c00aa10   docker.all-hands.dev/all-hands-ai/openhands:c00aa10

[malhotra5]

LGTM, thank you!