MM-43077 Allow inline JSON in config.json for advanced logging config (#23324)

* add AdvancedLoggingJSON to LogSettings and deprecate AdvancedLoggingConfig
* allow embedded JSON in config for advanced logging.

server/config/migrate.go

@@ -32,9 +32,11 @@ func Migrate(from, to string) error {
 		*sourceConfig.SamlSettings.PrivateKeyFile,
 	}
 
-	// Only migrate advanced logging config if it is not embedded JSON.
-	if !isJSONMap(*sourceConfig.LogSettings.AdvancedLoggingConfig) {
-		files = append(files, *sourceConfig.LogSettings.AdvancedLoggingConfig)
+	// Only migrate advanced logging config if it is a filespec.
+	dsn := sourceConfig.LogSettings.GetAdvancedLoggingConfig()
+	cfgSource, err := NewLogConfigSrc(dsn, source)
+	if err == nil && cfgSource.GetType() == LogConfigSrcTypeFile {
+		files = append(files, string(dsn))
 	}
 
 	files = append(files, sourceConfig.PluginSettings.SignaturePublicKeyFiles...)