gnu: python-doxyqml: Fix tests.

* gnu/packages/python-xyz.scm (python-doxyqml)[arguments]
<test-backend>: Use 'custom.
<test-flags>: Provide path to the test file.
[native-inputs]: Remove python-wheel.

Change-Id: Ic89f338fec5cfc434a2d1a25bd903232236c4129

gnu/packages/python-xyz.scm

@@ -6524,9 +6524,11 @@ other Python program.")
                (base32
                 "0skrs5i5pvpzvihgxw766zi1c9bbp33aisdldxgj470mlchvdgyy"))))
     (build-system pyproject-build-system)
+    (arguments
+     (list #:test-backend #~'custom
+           #:test-flags #~(list "tests/functional/tests.py")))
     (native-inputs
-     (list python-setuptools
-           python-wheel))
+     (list python-setuptools))
     (home-page "https://agateau.com/projects/doxyqml")
     (synopsis "Doxygen input filter for QML files")
     (description