fix(wg): correctly template facts

When setting facts to outputs of some other tasks or variables, they need
to be correctly templated and quoted, otherwise they're taken as is,
i.e., as text.

Signed-off-by: Matej Focko <me@mfocko.xyz>

roles/wg/tasks/generate_keypair.yml

@@ -16,5 +16,5 @@
 
 - name: Set key/pair facts
   ansible.builtin.set_fact:
-    wg_private_key: _generated_private_key.stdout
-    wg_public_key: _derived_public_key.stdout
+    wg_private_key: "{{ _generated_private_key.stdout }}"
+    wg_public_key: "{{ _derived_public_key.stdout }}"