Use `Gitlab::Geo.license_allows?` instead of checking license manually

ee/app/controllers/ee/admin/application_settings_controller.rb

@@ -55,7 +55,7 @@ module EE
           attrs << { compliance_frameworks: [] }
         end
 
-        if ::License.feature_available?(:geo) && ::Feature.enabled?(:maintenance_mode)
+        if ::Gitlab::Geo.license_allows? && ::Feature.enabled?(:maintenance_mode)
           attrs << :maintenance_mode
           attrs << :maintenance_mode_message
         end

ee/lib/ee/api/entities/application_setting.rb

@@ -20,8 +20,8 @@ module EE
           expose :updating_name_disabled_for_users, if: ->(_instance, _opts) { ::License.feature_available?(:disable_name_update_for_users) }
           expose :npm_package_requests_forwarding, if: ->(_instance, _opts) { ::License.feature_available?(:packages) }
           expose :group_owners_can_manage_default_branch_protection, if: ->(_instance, _opts) { ::License.feature_available?(:default_branch_protection_restriction_in_groups) }
-          expose :maintenance_mode, if: ->(_instance, _opts) { ::License.feature_available?(:geo) && ::Feature.enabled?(:maintenance_mode) }
-          expose :maintenance_mode_message, if: ->(_instance, _opts) { ::License.feature_available?(:geo) && ::Feature.enabled?(:maintenance_mode) }
+          expose :maintenance_mode, if: ->(_instance, _opts) { ::Gitlab::Geo.license_allows? && ::Feature.enabled?(:maintenance_mode) }
+          expose :maintenance_mode_message, if: ->(_instance, _opts) { ::Gitlab::Geo.license_allows? && ::Feature.enabled?(:maintenance_mode) }
         end
       end
     end

ee/lib/ee/api/settings.rb

@@ -47,7 +47,7 @@ module EE
               attrs = attrs.except(:group_owners_can_manage_default_branch_protection)
             end
 
-            unless ::License.feature_available?(:geo) && ::Feature.enabled?(:maintenance_mode)
+            unless ::Gitlab::Geo.license_allows? && ::Feature.enabled?(:maintenance_mode)
               attrs = attrs.except(:maintenance_mode, :maintenance_mode_message)
             end