Use get(..) instead of [..] for safe lookup of value (Fixed #7240)

A OnePassword field item might not have a value (property) when the user has omitted it (on purpose).

plugins/lookup/onepassword.py

@@ -462,10 +462,10 @@ def _parse_field(self, data_json, field_name, section_title=None):
                 # If the field name doesn't exist in the section, match on the value of "label"
                 # then "id" and return "value"
                 if field.get("label") == field_name:
-                    return field["value"]
+                    return field.get("value")
 
                 if field.get("id") == field_name:
-                    return field["value"]
+                    return field.get("value")
 
             # Look at the section data and get an indentifier. The value of 'id' is either a unique ID
             # or a human-readable string. If a 'label' field exists, prefer that since
@@ -475,10 +475,10 @@ def _parse_field(self, data_json, field_name, section_title=None):
             if section_title == current_section_title:
                 # In the correct section. Check "label" then "id" for the desired field_name
                 if field.get("label") == field_name:
-                    return field["value"]
+                    return field.get("value")
 
                 if field.get("id") == field_name:
-                    return field["value"]
+                    return field.get("value")
 
         return ""