fix: remove .only modifier from test to fix CI

[Bulletninja]

This PR fixes the failing CI test in PR module-federation#3544 by removing the .only modifier in packages/bridge/bridge-react/__tests__/bridge.spec.tsx. This modifier was causing Vitest to fail in CI environments with the error: [Vitest] Unexpected .only modifier.

I've verified locally that with the .only modifier, tests fail when run with --no-allowOnly flag (which matches CI behavior), and that removing it resolves the issue.

Related Issue

• Helps unblock PR feat(bridge-react): add support for custom createRoot on createBridgeComponent module-federation/core#3544
• Related to issue Support React v19 in @module-federation/bridge-react module-federation/core#3537 (Support React v19 in @module-federation/bridge-react)

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• All new and existing tests passed.

This small change should allow the important React 19 compatibility work in PR module-federation#3544 to proceed.