feat: support CSP nonce on injected style elements

[costajohnt]

Summary

Fixes #8273

Adds CSP nonce support to dynamically injected <style> elements in usePress and usePreventScroll. Without a nonce, these inline styles are blocked by strict Content Security Policy headers.

Approach

Following the approach suggested by @devongovett, this PR adds a getNonce() utility that reads the nonce from existing pseudo-standards:

function getNonce(): string | undefined {
  let meta = document.querySelector('meta[property="csp-nonce"]');
  return meta?.nonce || meta?.content || globalThis['__webpack_nonce__'];
}

This automatically works with:

• Vite — via html.cspNonce config (injects <meta property="csp-nonce">)
• webpack — via the __webpack_nonce__ global
• Any framework — that adds <meta property="csp-nonce" content="..."> to the document head

Changes

• @react-aria/utils: Added getNonce() utility + export
• @react-aria/interactions: Applied nonce to the <style> element in usePress
• @react-aria/overlays: Applied nonce to the <style> element in usePreventScroll

Test plan

• Added 5 unit tests for getNonce() covering: no config, meta nonce attribute, meta content attribute, webpack global, precedence
• All existing usePress tests pass (90/90)
• All existing overlay tests pass (191/191)

[reidbarber]

Thanks for the PR!

1. I think we can add globalThis: "readonly" to the languageOptions.globals in eslint.config.mjs (at line 460) to fix the lint step failing.
2. You also need to sign the CLA, then close and re-open the PR and the build should pass.