Define functions for global and private tenant cases (#1147)

Signed-off-by: Chang Liu <lc12251109@gmail.com>

public/plugin.tsx

@@ -74,6 +74,7 @@ const APP_LIST_FOR_READONLY_ROLE = [APP_ID_HOME, APP_ID_DASHBOARDS, APP_ID_OPENS
 const GLOBAL_TENANT_RENDERING_TEXT = 'Global';
 const PRIVATE_TENANT_RENDERING_TEXT = 'Private';
 const GLOBAL_TENANT = '';
+const PRIVATE_TENANT = '__user__';
 
 export class SecurityPlugin
   implements
@@ -169,9 +170,9 @@ export class SecurityPlugin
           dataType: 'string',
           render: (value: any[][]) => {
             let text = value[0][0];
-            if (text === null || text === GLOBAL_TENANT) {
+            if (isGlobalTenant(text)) {
               text = GLOBAL_TENANT_RENDERING_TEXT;
-            } else if (text.startsWith('__user__')) {
+            } else if (isPrivateTenant(text)) {
               text = PRIVATE_TENANT_RENDERING_TEXT;
             }
             text = i18n.translate('savedObjectsManagement.objectsTable.table.columnTenantName', {
@@ -213,3 +214,11 @@ export class SecurityPlugin
 
   public stop() {}
 }
+
+function isPrivateTenant(selectedTenant: string) {
+  return selectedTenant.startsWith('__user__');
+}
+
+function isGlobalTenant(selectedTenant: string) {
+  return selectedTenant === null || selectedTenant === GLOBAL_TENANT;
+}