test(replay): Skip flaky test in firefox

[mydea]

Skip some more tests for webkit & firefox, as they have been flaky sometimes.

Ran these 100x successfully!

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	20.46 KB (-0.01% 🔽)
@sentry/browser - ES5 CDN Bundle (minified)	63.38 KB (0%)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	19.06 KB (-0.03% 🔽)
@sentry/browser - ES6 CDN Bundle (minified)	56.43 KB (0%)
@sentry/browser - Webpack (gzipped + minified)	21.65 KB (0%)
@sentry/browser - Webpack (minified)	71.97 KB (0%)
@sentry/react - Webpack (gzipped + minified)	21.68 KB (0%)
@sentry/nextjs Client - Webpack (gzipped + minified)	52.02 KB (-0.35% 🔽)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	33.75 KB (+0.04% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	26.1 KB (+0.07% 🔺)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	43.86 KB (-0.01% 🔽)
@sentry/replay - Webpack (gzipped + minified)	37.94 KB (0%)
@sentry/browser + @sentry/tracing + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	62.06 KB (-0.01% 🔽)
@sentry/browser + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	55.12 KB (-0.01% 🔽)