Fix extra protocol field is required

plugins/netbox-rps-plugin/netbox_rps_plugin/forms.py

@@ -23,7 +23,9 @@ from .models import (
 class MappingForm(NetBoxModelForm):
     """Mapping form definition class"""
 
-    extra_protocols = forms.MultipleChoiceField(choices=ExtraProtocolChoices)
+    extra_protocols = forms.MultipleChoiceField(
+        choices=ExtraProtocolChoices, required=False
+    )
 
     class Meta:
         model = Mapping