[Easy]: Fix outdated default React test

### Problem Statement

The current test still checks for learn react text and does not match the real UI.

### Files and Scope

event-dappp/src/App.test.js

### Acceptance Criteria

- [ ] Test no longer checks for learn react text
- [ ] Test validates actual visible app content
- [ ] Test passes locally with npm test
- [ ] Test remains stable in watch mode

### Test Plan

Run npm test in frontend folder.
Verify updated test passes.
Make a temporary wrong assertion and confirm test fails.

Open event-dappp/src/App.test.js and inspect the current assertion alongside the visible UI rendered by the app. Run npm test from the frontend folder, replace the outdated “learn react” expectation with an assertion for actual visible app content, and confirm the test passes in watch mode and fails with a temporary incorrect assertion.

Written by the indexing model from the issue text.