Require Sphinx-7.* instead of Sphinx-7.2.*

Remove package pinning workarounds introduced for quantumlib#6400.
Also remove an old pinning of the Jinja2 package which
is unlikely to be still needed.

rtd_docs/requirements.txt

@@ -1,16 +1,5 @@
 # For generating documentation.
-
-# TODO(#6400,juhas) - upgrade Sphinx and remove the package pins below -------
-alabaster<=0.7.13
-sphinxcontrib-applehelp<=1.0.7
-sphinxcontrib-devhelp<=1.0.5
-sphinxcontrib-htmlhelp<=2.0.4
-sphinxcontrib-qthelp<=1.0.6
-sphinxcontrib-serializinghtml<=1.1.9
-# End of TODO ----------------------------------------------------------------
-
 myst-parser
-Sphinx~=7.2.6
+Sphinx==7.*
 sphinx_rtd_theme
 sphinx-notfound-page
-Jinja2<=3.0.3