libint: add Python as build dependency (#30870)

Installation process of libint runs a Python script:
<69cc7b9bc6/export/cmake/CMakeLists.txt.export (L410)>.
If Python isn't explicitly listed as build dependency, system Python will be
picked up, which can cause troubles.

var/spack/repos/builtin/packages/libint/package.py

@@ -55,6 +55,7 @@ class Libint(AutotoolsPackage):
     depends_on('autoconf@2.52:', type='build')
     depends_on('automake', type='build')
     depends_on('libtool', type='build')
+    depends_on('python', type='build')
 
     # Libint 2 dependencies
     # Fixme: Can maintainers please confirm that this is a required dependency