gnu: Make nothing depend on QtWebKit.

This is required for <https://issues.guix.gnu.org/53289>.

* gnu/packages/qt.scm (python-pyqt)[inputs]: Remove qtwebkit.
(python-pyqt-without-qtwebkit): Remove variable.
(python-pyqtwebengine)[inputs]: Replace python-pyqt-without-qtwebkit with
python-pyqt.
* gnu/packages/backup.scm (vorta)[inputs]: Likewise.
* gnu/packages/ebook.scm (calibre)[inputs]: Likewise.
[arguments]: Adjust accordingly.
* gnu/packages/education.scm (anki)[inputs]: Replace
python-pyqt-without-qtwebkit with python-pyqt.
* gnu/packages/kde-games.scm (kajongg)[inputs]: Likewise.
* gnu/packages/maths.scm (veusz)[inputs]: Likewise.
* gnu/packages/music.scm (frescobaldi)[inputs]: Likewise.
(picard)[inputs]: Likewise.
* gnu/packages/orange.scm (orange)[inputs]: Likewise.
* gnu/packages/pdf.scm (flyer-composer)[inputs]: Likewise.
* gnu/packages/python-check.scm (python-pytest-qt)[propagated-inputs]: Likewise.
* gnu/packages/python-xyz.scm (python-qtconsole)[propagated-inputs]: Likewise.
(python-pyqtgraph)[propagated-inputs]: Likewise.
* gnu/packages/radio.scm (gnuradio)[inputs]: Likewise.
* gnu/packages/video.scm (openshot)[inputs]: Likewise.
* gnu/packages/vpn.scm (openconnect-sso)[inputs]: Likewise.
* gnu/packages/web-browsers.scm (qutebrowser)[inputs]: Likewise.

gnu/packages/python-check.scm

@@ -1678,7 +1678,7 @@ libraries.")
              (setenv "QT_QPA_PLATFORM" "offscreen")
              #t)))))
     (propagated-inputs
-     (list python-pyqt-without-qtwebkit))
+     (list python-pyqt))
     (native-inputs
      (list python-pytest python-pytest-runner python-setuptools-scm))
     (home-page "https://github.com/pytest-dev/pytest-qt")