Use custom ASN if defined in inventory

Should be defined in partner's general.yaml file, e.g.
partner:
  LHCONE:
    asn: 22442

geant/gap_ansible/roles/bgp_config/tasks/merge_vars.yaml

@@ -33,3 +33,11 @@
     import_policies_v6: "{{ bgp_custom.policies.import.v6 }}"
     export_policies_v4: "{{ bgp_custom.policies.export.v4 }}"
     export_policies_v6: "{{ bgp_custom.policies.export.v6 }}"
+
+- name: Set ASN override if defined in Partners inventory file
+  when: >
+    subscription.product.product_type | upper in l3_service_types.vprn
+    and
+    partner[subscription.product.product_type | upper].asn is defined
+  ansible.builtin.set_fact:
+    partner_custom_asn: "{{ partner[subscription.product.product_type | upper].asn }}"

geant/gap_ansible/roles/bgp_config/templates/nokia/deploy/bgp_neighbor.j2

@@ -17,7 +17,11 @@
                     <description>-- IPv6 Peering with {{ partner_name | upper }} --</description>
                     <group>{{ bgp.group.ipv6 }}</group>
                     {% endif %}
+                    {% if partner_custom_asn is defined %}
+                    <peer-as>{{ partner_custom_asn }}</peer-as>
+                    {% else %}
                     <peer-as>{{ partner.asn }}</peer-as>
+                    {% endif %}
                   {% if neighbor.send_default_route %}
                     <send-default>
                       <{{ neighbor.ip_type }}>true</{{ neighbor.ip_type }}>