build(serverless): Remove unused build check

[mydea]

It seems this is failing (sometimes?) and I don't think we need it anymore.

e.g. see https://github.com/getsentry/sentry-javascript/actions/runs/8067785899/job/22039493880?pr=10825

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay, Feedback) - Webpack (gzipped)	77.27 KB (-0.02% 🔽)
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	68.54 KB (-0.02% 🔽)
@sentry/browser (incl. Tracing, Replay with Canvas) - Webpack (gzipped)	72.45 KB (-0.02% 🔽)
@sentry/browser (incl. Tracing, Replay) - Webpack with treeshaking flags (gzipped)	62.08 KB (+0.04% 🔺)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	32.7 KB (-0.08% 🔽)
@sentry/browser (incl. browserTracingIntegration) - Webpack (gzipped)	32.7 KB (-0.08% 🔽)
@sentry/browser (incl. Feedback) - Webpack (gzipped)	30.91 KB (-0.02% 🔽)
@sentry/browser (incl. sendFeedback) - Webpack (gzipped)	30.91 KB (-0.02% 🔽)
@sentry/browser - Webpack (gzipped)	22.18 KB (-0.08% 🔽)
@sentry/browser (incl. Tracing, Replay, Feedback) - ES6 CDN Bundle (gzipped)	75.69 KB (-0.01% 🔽)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	67.39 KB (-0.1% 🔽)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	33.17 KB (-0.2% 🔽)
@sentry/browser - ES6 CDN Bundle (gzipped)	24.72 KB (-0.06% 🔽)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	211 KB (-0.02% 🔽)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	99.72 KB (-0.05% 🔽)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	73.92 KB (-0.06% 🔽)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	36.26 KB (-0.07% 🔽)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	68.79 KB (-0.06% 🔽)
@sentry/react - Webpack (gzipped)	22.19 KB (-0.12% 🔽)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	85.23 KB (-0.02% 🔽)
@sentry/nextjs Client - Webpack (gzipped)	49.57 KB (-0.12% 🔽)
@sentry-internal/feedback - Webpack (gzipped)	17.14 KB (0%)