fix: Handle unhashable BooleanField representation value

[emfpdlzj]

This is a small consistency fix for BooleanField.to_representation(), matching the existing TypeError handling used by to_internal_value() while preserving the existing bool(value) fallback.

Summary

BooleanField.to_representation() now handles unhashable values consistently with to_internal_value().

Previously, values like [], {}, or set() could raise TypeError during membership checks before reaching the existing bool(value) fallback. This change suppresses TypeError around the explicit true/false/null token checks, allowing unrecognized unhashable values to be represented by their truthiness.

Test

• Added BooleanField representation coverage for empty and non-empty unhashable collection values.
• Ran:
  uv run --no-project --with 'django==5.2.*' --with 'pytest==9.*' --with pytest-django --with dj-database-url --with importlib-metadata --with pytz -m pytest tests/test_fields.py -k BooleanField