bugfix for conduit py module install path (#23057)

* add lost logic for setting python install dir

* conduit: fix missing pass of python install path during build

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

@@ -422,6 +422,9 @@ def hostconfig(self, spec, prefix):
             cfg.write("# python from spack \n")
             cfg.write(cmake_cache_entry("PYTHON_EXECUTABLE",
                       spec['python'].command.path))
+            cfg.write("# python module install dir\n")
+            cfg.write(cmake_cache_entry("PYTHON_MODULE_INSTALL_PREFIX",
+                      site_packages_dir))
         else:
             cfg.write(cmake_cache_entry("ENABLE_PYTHON", "OFF"))