py-matplotlib: drop test dep (#43765)

test dependencies constrains build / link type deps, so avoid that

var/spack/repos/builtin/packages/py-matplotlib/package.py

@@ -266,7 +266,8 @@ class PyMatplotlib(PythonPackage):
 
     # Testing dependencies
     # Required
-    depends_on("freetype@2.6.1 build_system=autotools", type="test")
+    # https://github.com/spack/spack/issues/43597
+    # depends_on("freetype@2.6.1 build_system=autotools", type="test")
     depends_on("py-pytest@7:", type="test")
 
     msg = "MacOSX backend requires macOS 10.12+"