-D translation_progress_classes=0 doesn't convert to False as it should

[liborjelinek]

Describe the bug

-D, --define parameter to sphinx-build should convert 0 to False as documented.

However, for recently added translation_progress_classes option it doesn't work.

How to Reproduce

sphinx-build -b html -D language=cs -D translation_progress_classes=0 source build

says

WARNING: The config value `translation_progress_classes` has to be a one of (True, False, 'translated', 'untranslated'), but `0` is given.

Configuration error:
translation_progress_classes must be True, False, "translated" or "untranslated"

Environment Information

"sphinx==8.1.3"

Sphinx extensions

No response

Additional context

No response