test(mobile): use explicit expected values in isServer consistency test (#355)

Co-authored-by: 김윤호 yunho <kimyouknow@naver.com>

Author: guesung

packages/mobile/src/utils/isServer/isServer.test.ts

@@ -13,7 +13,8 @@ describe('isServer', () => {
     const secondCall = isServer();
     const thirdCall = isServer();
 
-    expect(firstCall).toBe(secondCall);
-    expect(secondCall).toBe(thirdCall);
+    expect(firstCall).toBe(false);
+    expect(secondCall).toBe(false);
+    expect(thirdCall).toBe(false);
   });
 });