Update OAuth token endpoint in graph API handler constants

Author: ShocOne

apihandlers/graph/graph_api_handler_constants.go

@@ -5,8 +5,8 @@ package graph
 const (
 	APIName                            = "microsoft graph"     // APIName: represents the name of the API.
 	DefaultBaseDomain                  = "graph.microsoft.com" // DefaultBaseDomain: represents the base domain for the graph instance.
-	OAuthTokenEndpoint                 = "graph.microsoft.com" // OAuthTokenEndpoint: The endpoint to obtain an OAuth token.
-	BearerTokenEndpoint                = "graph.microsoft.com" // BearerTokenEndpoint: The endpoint to obtain a bearer token.
+	OAuthTokenEndpoint                 = "/oauth2/v2.0/token"  // OAuthTokenEndpoint: The endpoint to obtain an OAuth token.
+	BearerTokenEndpoint                = ""                    // BearerTokenEndpoint: The endpoint to obtain a bearer token.
 	TokenRefreshEndpoint               = "graph.microsoft.com" // TokenRefreshEndpoint: The endpoint to refresh an existing token.
 	TokenInvalidateEndpoint            = "graph.microsoft.com" // TokenInvalidateEndpoint: The endpoint to invalidate an active token.
 	BearerTokenAuthenticationSupport   = true                  // BearerTokenAuthSuppport: A boolean to indicate if the API supports bearer token authentication.