Suppress new scs warning from docs output (backport #1580) (#1581)

jupyter-sphinx causes the docs build to fail for any warning so we need
to suppress warnings for the docs to build. I am not sure if there is
something we should be doing in this specific warning's case. The
warning text is:

> `/.tox/docs/lib/python3.13/site-packages/scs/__init__.py:83:
UserWarning: `
> `Converting A to a CSC (compressed sparse column) matrix; may take a
while.`

The code emitting the warning in scs has not changed recently but
something else in the pipeline must have changed to generate a matrix
differently than it did before.<hr>This is an automatic backport of pull
request #1580 done by [Mergify](https://mergify.com).

Co-authored-by: Will Shanks <willshanks@us.ibm.com>

Author: mergify[bot]

docs/manuals/verification/state_tomography.rst

@@ -127,6 +127,16 @@ details). For example, if ``cvxpy`` is installed we can use the
 :func:`~.cvxpy_gaussian_lstsq` fitter, which allows constraining the fit to be
 PSD without requiring rescaling.
 
+.. jupyter-execute::
+    :hide-code:
+
+    import warnings
+    # Hide warning from scs from output; is there a way to avoid the warning?
+    # Full warning line:
+    #   /.tox/docs/lib/python3.13/site-packages/scs/__init__.py:83: UserWarning: 
+    #   Converting A to a CSC (compressed sparse column) matrix; may take a while.
+    warnings.filterwarnings("ignore", module=r"scs", message="Converting A to a CSC")
+
 .. jupyter-execute::
 
     try: