LaTeX: user injected \color commands in topic or admonition boxes may cause color leaks in PDF due to upstream framed.sty bug

[jfbu]

Describe the bug

Boxes may leak colors from inside. Here is an example, with 5.x/5ffe1e87. It would have been even worse before merge of #10619 and also c327f09 (relates #10610).

How to Reproduce

Color leaks
===========

.. contents::

A section
---------

Paragraph should be black but isn't.

.. warning:: This is blue as requested.

   BUT FRAMING IS INVISIBLE!


Paragraph should be black. It is... by luck probably.

.. caution:: Beware LaTeX color leaks! (which may make things invisible).

   They are caused by an upstream framed.sty bug, but we know the cure.

Paragraph should be black.

and use this for conf.py

latex_elements = {
    'preamble': r"""
\def\sphinxstyletopictitle #1{\leavevmode\color{red}% color for contents
                                \textcolor{green}{\textbf{#1}}% colored title
                                \par\medskip}
\renewenvironment{sphinxwarning}[1]
  {\begin{sphinxheavybox}\sphinxstrong{#1} \color{blue}}{\end{sphinxheavybox}}
""",
}

Expected behavior

No color leaks...

Your project

See example

Screenshots

OS

Mac

Python version

CPython 3.10.4

Sphinx version

5.x/5ffe1e879

Sphinx extensions

No response

Extra tools

No response

Additional context

This is caused by an upstream framed.sty bug which constructs a \vbox without needed extra group for compatibility with the way \color command internally works.

I will push a fix next.