fix: resolve RFC 7643 inconsistency in ServiceProviderConfig authenticationSchemes schema

RFC 7643 contains a documented inconsistency between the ServiceProviderConfig
schema definition (section 8.7.2) and the example data (section 8.5):

- Schema definition only specifies 4 sub-attributes for authenticationSchemes:
  name, description, specUri, documentationUri
- Example data contains additional attributes: type, primary

This inconsistency is acknowledged in RFC Errata ID 7921, where the schema
definition is incomplete compared to the actual usage patterns shown in
examples and implementations.

Author: azmeuk

samples/rfc7643-8.7.2-schema-service_provider_configuration.json

@@ -177,6 +177,24 @@
             "returned": "default",
             "mutability": "readOnly",
             "subAttributes": [
+                {
+                    "name": "type",
+                    "type": "string",
+                    "multiValued": false,
+                    "description": "The authentication scheme.",
+                    "required": true,
+                    "canonicalValues": [
+                        "oauth",
+                        "oauth2",
+                        "oauthbearertoken",
+                        "httpbasic",
+                        "httpdigest"
+                    ],
+                    "caseExact": false,
+                    "mutability": "readOnly",
+                    "returned": "default",
+                    "uniqueness": "none"
+                },
                 {
                     "name": "name",
                     "type": "string",
@@ -226,6 +244,17 @@
                     "mutability": "readOnly",
                     "returned": "default",
                     "uniqueness": "none"
+                },
+                {
+                    "name": "primary",
+                    "type": "boolean",
+                    "multiValued": false,
+                    "description": "A Boolean value indicating the 'primary' or preferred attribute value for this attribute.",
+                    "required": false,
+                    "caseExact": false,
+                    "mutability": "readOnly",
+                    "returned": "default",
+                    "uniqueness": "none"
                 }
             ]
         }