Wagtail 7.2 Maintenance

[rachelhsmith]

This pull request updates the project's Python and Wagtail version support, removes support for Python 3.9, and updates development dependencies.

Python version support:

• Dropped support for Python 3.9 and added support for Python 3.14 throughout the project

Wagtail version support:

• Added testing and support for Wagtail 7.2, and updated test configurations to use Wagtail 7.0 and 7.2. Removed references to older Wagtail versions.

Dependency updates:

• Updated development dependencies in pyproject.toml to newer versions of pre-commit, pytest, pytest-django, and ruff, and increased the minimum required Wagtail version for development to 7.0.

Project metadata:

• Updated the Python version classifiers and the minimum required Python version in pyproject.toml to reflect the new supported versions.

Changelog:

• Updated CHANGELOG.md to document the new Python and Wagtail version support.

[nickmoreton]

Looks good I left one suggestion

[nickmoreton]

I'm going to rework this to also test for wagtail 7.2