feat(v8/browser): Remove _eventFromIncompleteOnError usage

[AbhiPrasad]

closes #5842

Also deletes GlobalHandlers integration deprecated export while I'm here.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay, Feedback) - Webpack (gzipped)	78.18 KB (-0.2% 🔽)
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	69.39 KB (-0.26% 🔽)
@sentry/browser (incl. Tracing, Replay with Canvas) - Webpack (gzipped)	73.32 KB (-0.24% 🔽)
@sentry/browser (incl. Tracing, Replay) - Webpack with treeshaking flags (gzipped)	63.04 KB (-0.23% 🔽)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	33.36 KB (-0.47% 🔽)
@sentry/browser (incl. browserTracingIntegration) - Webpack (gzipped)	33.23 KB (-0.46% 🔽)
@sentry/browser (incl. Feedback) - Webpack (gzipped)	31.21 KB (-0.5% 🔽)
@sentry/browser (incl. sendFeedback) - Webpack (gzipped)	31.22 KB (-0.5% 🔽)
@sentry/browser - Webpack (gzipped)	22.5 KB (-0.62% 🔽)
@sentry/browser (incl. Tracing, Replay, Feedback) - ES6 CDN Bundle (gzipped)	76.21 KB (-0.21% 🔽)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	67.74 KB (-0.24% 🔽)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	33.5 KB (-0.48% 🔽)
@sentry/browser - ES6 CDN Bundle (gzipped)	24.58 KB (-0.61% 🔽)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	213.73 KB (-0.16% 🔽)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	101.53 KB (-0.34% 🔽)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	73.91 KB (-0.47% 🔽)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	36.65 KB (-0.41% 🔽)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	69.75 KB (-0.25% 🔽)
@sentry/react - Webpack (gzipped)	22.53 KB (-0.62% 🔽)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	87.35 KB (-0.23% 🔽)
@sentry/nextjs Client - Webpack (gzipped)	51.54 KB (-0.36% 🔽)
@sentry-internal/feedback - Webpack (gzipped)	17.22 KB (0%)