fix: Handle unhandled promise rejection in stylesheet loading

[Lihexs]

Summary

Fix UnhandledPromiseRejection crash in Jest when CSS stylesheet resources fail to load.

When a stylesheet fails to load, the Promise created with link.onerror = reject
was not being caught, causing Node.js/Jest to crash with UnhandledPromiseRejection.

Changes:

1. Added .catch(() => {}) to stylesheet loading Promises in ReactFiberConfigDOM.js (3 locations)
2. Fixed test assertion order in ReactDOMFloat-test.js to match actual event dispatch order
3. Unskipped the "can delay commit until css resources error" test

Note: The empty .catch() handler is intentional - React already tracks the error state via state.loading |= Errored, so the catch is only needed to prevent Node.js from crashing on unhandled rejection.

How did you test this change?

Unskipped and ran the previously failing test:

yarn test packages/react-dom/src/__tests__/ReactDOMFloat-test.js -t "can delay commit until css resources error"

Before fix: Jest crashes with UnhandledPromiseRejection

After fix: Test passes successfully

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