Only load saml settings when we have related secrets

Without this change the IdpMetaParser would give an error
in the Devise initializer when starting the application.

I found it annoying to have to connect to the VPN so
I decided to add this condition.

Reviewer, feel free to consider this commit unnecessary
and ask to revert it.

config/initializers/devise.rb

@@ -286,11 +286,14 @@ Devise.setup do |config|
                   Rails.application.secrets.wordpress_oauth2_secret,
                   client_options: { site: Rails.application.secrets.wordpress_oauth2_site },
                   setup: ->(env) { OmniauthTenantSetup.wordpress_oauth2(env) }
+  saml_settings = {}
+  if Rails.application.secrets.saml_idp_metadata_url.present?
     idp_metadata_parser = OneLogin::RubySaml::IdpMetadataParser.new
     saml_settings = idp_metadata_parser.parse_remote_to_hash(Rails.application.secrets.saml_idp_metadata_url)
     saml_settings[:idp_sso_service_url] = Rails.application.secrets.saml_idp_sso_service_url
     saml_settings[:sp_entity_id] = Rails.application.secrets.saml_sp_entity_id
     saml_settings[:allowed_clock_drift] = 1.minute
+  end
   config.omniauth :saml, saml_settings
 
   # ==> Warden configuration