feat(browser): Export event builder methods for use in other SDKs

[krystofwoldrich]

Exporting these methods will enable RN to change behavior independent of JS SDK. It will also make the RN client not depend on the BrowserClient instance.

Context:

• fix(event): Message event includes current stack trace in threads sentry-react-native#2694

#skip-changelog

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	19.72 KB (+0.05% 🔺)
@sentry/browser - ES5 CDN Bundle (minified)	61.13 KB (+0.03% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	18.51 KB (+0.05% 🔺)
@sentry/browser - ES6 CDN Bundle (minified)	54.66 KB (+0.03% 🔺)
@sentry/browser - Webpack (gzipped + minified)	20.28 KB (0%)
@sentry/browser - Webpack (minified)	66.33 KB (0%)
@sentry/react - Webpack (gzipped + minified)	20.3 KB (0%)
@sentry/nextjs Client - Webpack (gzipped + minified)	47.5 KB (0%)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	26.69 KB (-0.04% 🔽)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	25.14 KB (-0.04% 🔽)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	41.71 KB (-0.06% 🔽)
@sentry/replay - Webpack (gzipped + minified)	37.98 KB (-0.07% 🔽)

[krystofwoldrich]

🙏