Removing secondary sidebar still takes up width

[jack6th]

Describe the bug

From the documentation there are two ways to remove the secondary sidebar from a page: via page-wide metadata :html_theme.sidebar_secondary.remove: or via html_theme_options in conf.py and set the "secondary_sidebar_items" for a particular page into an empty list.

pydata_sphinx_theme works correctly.

In sphinx_book_theme the secondary sidebar actually still exists and takes up width, though empty.

It is like the fixed pydata_sphinx_theme issue https://github.com/pydata/pydata-sphinx-theme/issues/1686

Reproduce the bug

remove the secondary sidebar from a page: via page-wide metadata :html_theme.sidebar_secondary.remove: or via html_theme_options in conf.py and set the "secondary_sidebar_items"

List your environment

No response