Fix Rubocop offenses

Author: MrSerth

lib/enmeshed/connector.rb

@@ -4,8 +4,8 @@ module Enmeshed
   class ConnectorError < StandardError; end
 
   class Connector
-    API_KEY = Settings.omniauth&.nbp&.enmeshed&.connector_api_key
-    CONNECTOR_URL = Settings.omniauth&.nbp&.enmeshed&.connector_url
+    API_KEY = Settings.dig(:omniauth, :nbp, :enmeshed, :connector_api_key)
+    CONNECTOR_URL = Settings.dig(:omniauth, :nbp, :enmeshed, :connector_url)
     API_SCHEMA = JSONSchemer.openapi(YAML.safe_load_file(Rails.root.join('lib/enmeshed/api_schema.yml'), permitted_classes: [Time, Date]))
 
     # @return [String] The address of the enmeshed account.

lib/enmeshed/relationship_template.rb

@@ -8,7 +8,7 @@ class RelationshipTemplate < Object
     # To minimize the risk of a template expiring before submission, we set the validity to 12 hours.
     VALIDITY_PERIOD = 12.hours
     # The display name of the service as shown in the enmeshed app.
-    DISPLAY_NAME = Settings.omniauth&.nbp&.enmeshed&.display_name
+    DISPLAY_NAME = Settings.dig(:omniauth, :nbp, :enmeshed, :display_name)
     # These attributes are mandatory in the app and must be provided.
     # See https://enmeshed.eu/integrate/attribute-values for more attributes.
     REQUIRED_ATTRIBUTES = %w[GivenName Surname EMailAddress AffiliationRole].freeze
@@ -117,7 +117,7 @@ def shared_attributes
     end
 
     def relationship_attributes
-      if Settings.omniauth&.nbp&.enmeshed&.allow_certificate_request
+      if Settings.dig(:omniauth, :nbp, :enmeshed, :allow_certificate_request)
         [
           {
             '@type': 'CreateAttributeRequestItem',