ref(serverless): Properly deprecate rethrowAfterCapture option

[mydea]

This is unused since v6 but we never got around to actually remove this, so let's properly deprecate this for v8.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	84.24 KB (-0.03% 🔽)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	31.41 KB (-0.02% 🔽)
@sentry/browser - Webpack (gzipped)	22 KB (0%)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	78.69 KB (-0.01% 🔽)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	28.52 KB (-0.01% 🔽)
@sentry/browser - ES6 CDN Bundle (gzipped)	20.59 KB (-0.01% 🔽)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	254.14 KB (0%)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	86.42 KB (0%)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	61.23 KB (0%)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	31.38 KB (-0.02% 🔽)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	84.26 KB (-0.02% 🔽)
@sentry/react - Webpack (gzipped)	22.03 KB (0%)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	102.23 KB (+0.03% 🔺)
@sentry/nextjs Client - Webpack (gzipped)	50.98 KB (+0.06% 🔺)