"Strong" text is not formatted as bold in figure or figure-md directives

[72757373656c6c]

Describe the bug

context
Please take a look at the example in either of the links below. They will illustrate the issue.

1. https://jupyterbook.org/en/stable/content/figures.html#markdown-figures.

   Source: This is a caption in **Markdown**!
   Expect: This is a caption in Markdown!
   Instead: This is a caption in Markdown!

2. https://myst-parser.readthedocs.io/en/latest/syntax/images_and_figures.html#id2

   Source: This is a caption in __*Markdown*__
   Expect: This is a caption in Markdown
   Instead: This is a caption in Markdown

There is markdown syntax for bold but the html/css output is not rendered as bold.

expectation
I expected the word "Markdown" to be bold in the example.

bug
But instead the word "Markdown" was not bold in the example.

No errors.

I found bug #122, but this is specific to the various figure directives.

problem
This is a problem for people using the figure directives and expecting that markdown bold text to be rendered bold.

The font-weight for strong is not correct when under the figure figcaption tags.

Reproduce the bug

Include bold text in a figure or figure-md directive. See above.

List your environment

sphinx-book-theme 1.1.2
pydata-sphinx-theme 0.15.2
myst-parser 2.0.0
Sphinx 7.2.6