Fix template for Rpackage in spack create command (#21776)

The signature for configure_args in the template for new
RPackage packages was incorrect (different than what is
defined and used in lib/spack/spack/build_systems/r.py)

See issue #21774

lib/spack/spack/cmd/create.py

@@ -322,7 +322,7 @@ class RPackageTemplate(PackageTemplate):
     # depends_on('r-foo', type=('build', 'run'))"""
 
     body_def = """\
-    def configure_args(self, spec, prefix):
+    def configure_args(self):
         # FIXME: Add arguments to pass to install via --configure-args
         # FIXME: If not needed delete this function
         args = []