fix: introduce Error Boundaries to handle unexpected failures (#7671)

Two new components have been updated via plugin system: ErrorBoundary and Fallback.
These components can be overridden by user plugins.

Refs #7647

config/jest/jest.unit.config.js

@@ -18,6 +18,7 @@ module.exports = {
     '<rootDir>/test/unit/components/online-validator-badge.jsx',
     '<rootDir>/test/unit/components/live-response.jsx',
   ],
+  silent: true, // set to `false` to allow console.* calls to be printed
   transformIgnorePatterns: [
     '/node_modules/(?!(react-syntax-highlighter)/)'
   ]