Remove deprecated ImageFont.getsize and related functions for Pillow 10.0.0

[radarhere]

This removes functions deprecated in #6381.

It includes

• the core change, Removed ImageFont.getsize and related functions hugovk/Pillow#99, originally a part of Remove deprecations for Pillow 10.0.0 #7059
• adding a new test for ImageDraw2.textbbox(), a variation on Improve tests after removing deprecated textsize hugovk/Pillow#100
• only checking width and height of transposed fonts once, a variation on a suggestion for Improve tests after removing deprecated textsize hugovk/Pillow#100
• an update to preserve backwards compatibility of line spacing by using double the stroke width, one possibility from Remove deprecations for Pillow 10.0.0 #7059 (comment)

[hugovk]

This bit should be moved down as well.

Or, does Sphinx automatically create this anchor, and can we remove it?

Suggested change

.. _Font size and offset methods:

[radarhere]

The anchor was only being used from ImageDraw documentation that needed to be removed.

I've pushed a commit to remove both.

[radarhere]

The Ubuntu failures are also happening on main - https://github.com/python-pillow/Pillow/actions/runs/4656595509

[hugovk]

Tests/test_qt_image_qapplication.py::test_sanity Fatal Python error: Aborted

PyQt6 6.5.0 was released two hours ago: https://pypi.org/project/PyQt6/6.5.0/

[radarhere]

#7081 was merged as a temporary workaround for the Qt failures.