Fix nxos_vpc issues (#28188)

* fix for nxos_vpc issues

* fix unit tests

* clean documentation

test/integration/nxos.yaml

@@ -168,6 +168,15 @@
             failed_modules: "{{ failed_modules }} + [ 'nxos_vrrp' ]"
             test_failed: true
 
+    - block:
+      - include_role:
+          name: nxos_vpc
+        when: "limit_to in ['*', 'nxos_vpc']"
+      rescue:
+        - set_fact:
+            failed_modules: "{{ failed_modules }} + [ 'nxos_vpc' ]"
+            test_failed: true
+
     - block:
       - include_role:
           name: nxos_vtp_domain