fix(@schematics/angular): clarify tslint:recommended warning message

Closes: #17311

Author: alan-agius4

packages/schematics/angular/migrations/update-10/update-tslint.ts

@@ -129,8 +129,8 @@ export default function (): Rule {
       (extendsAst.kind === 'string' && extendsAst.value !== 'tslint:recommended') ||
       (extendsAst.kind === 'array' && extendsAst.elements.some(e => e.value !== 'tslint:recommended'))
     ) {
-      logger.warn(`tslint configuration does not extend "tslint:recommended".`
-        + '\nMigration will terminate as some rules might conflict.');
+      logger.warn(`tslint configuration does not extend "tslint:recommended" or it extends multiple configurations.`
+        + '\nSkipping rule changes as some rules might conflict.');
 
       return;
     }