[MM-57085] Remove UseNewSAMLLibrary experimental setting (#26392)

Co-authored-by: Mattermost Build <build@mattermost.com>

server/platform/services/telemetry/telemetry.go

@@ -775,7 +775,6 @@ func (ts *TelemetryService) trackConfig() {
 		"isdefault_client_side_cert_check":    isDefault(*cfg.ExperimentalSettings.ClientSideCertCheck, model.ClientSideCertCheckPrimaryAuth),
 		"link_metadata_timeout_milliseconds":  *cfg.ExperimentalSettings.LinkMetadataTimeoutMilliseconds,
 		"restrict_system_admin":               *cfg.ExperimentalSettings.RestrictSystemAdmin,
-		"use_new_saml_library":                *cfg.ExperimentalSettings.UseNewSAMLLibrary,
 		"enable_shared_channels":              *cfg.ExperimentalSettings.EnableSharedChannels,
 		"enable_remote_cluster_service":       *cfg.ExperimentalSettings.EnableRemoteClusterService && cfg.FeatureFlags.EnableRemoteClusterService,
 		"enable_app_bar":                      !*cfg.ExperimentalSettings.DisableAppBar,