Update calculation of `trunk_suffix`

geant/gap_ansible/roles/iptrunk/templates/juniper/trunk_interface.j2

@@ -25,7 +25,10 @@
     {# I need to sort the source and the destination alfabetically #}
     {% set trunk_direction_name = [ local.name.split(".")[1] | upper, remote.name.split(".")[1] | upper ] %}
     {% set trunk_direction_name_sorted = trunk_direction_name|sort %}
+
+    {% if wfo_trunk.iptrunk.iptrunk_description_suffix is not none %}
     {% set trunk_suffix = '-'+wfo_trunk.iptrunk.iptrunk_description_suffix if wfo_trunk.iptrunk.iptrunk_description_suffix|length > 0 %}
+    {% endif %}
     {##}
     interfaces {
     replace: {{local.ae_name}} {

geant/gap_ansible/roles/iptrunk/templates/nokia/trunk_interface.j2

@@ -26,7 +26,9 @@
     {% set trunk_direction_name = [ local.name.split(".")[1] | upper, remote.name.split(".")[1] | upper ] %}
     {% set trunk_direction_name_sorted = trunk_direction_name|sort %}
 
+    {% if wfo_trunk.iptrunk.iptrunk_description_suffix is not none %}
     {% set trunk_suffix = '-'+wfo_trunk.iptrunk.iptrunk_description_suffix if wfo_trunk.iptrunk.iptrunk_description_suffix|length > 0 %}
+    {% endif %}
 {##}
 {% for member in local.members %}
       <port xmlns="urn:nokia.com:sros:ns:yang:sr:conf" xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0" xmlns:nokia-attr="urn:nokia.com:sros:ns:yang:sr:attributes" alu:operation="replace">