When using import_yaml to load YAML data with multi-line scalars (using |),
the newlines were being rendered as literal \n instead of actual newlines
when passed through Jinja templates.

This fix adds an _unescape_newlines function that recursively converts
literal \n sequences back to actual newlines in the context dictionary
before it's used for templating.

- Added _unescape_newlines function to salt/utils/templates.py
- Applied unescape to context before creating decoded_context
- Updated test to remove to_dict filter reference