feat(utils): Add propagationContextFromHeaders

[lforst]

Adds a simpler alternative to tracingContextFromHeaders which is deprecated with this PR. tracingContextFromHeadrs is returning duplicate data, and the value it returns is gonna be useless in a world where spans do not take traceparent data and dynamic sampling contexts directly.

I replaced the deprecated instances in places where it was easy and just added an eslint ignore in places where we will need to refactor in any case.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay, Feedback) - Webpack (gzipped)	78.1 KB (-0.1% 🔽)
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	69.34 KB (-0.06% 🔽)
@sentry/browser (incl. Tracing, Replay with Canvas) - Webpack (gzipped)	73.2 KB (-0.11% 🔽)
@sentry/browser (incl. Tracing, Replay) - Webpack with treeshaking flags (gzipped)	62.95 KB (-0.09% 🔽)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	33.36 KB (-0.15% 🔽)
@sentry/browser (incl. browserTracingIntegration) - Webpack (gzipped)	33.21 KB (-0.15% 🔽)
@sentry/browser (incl. Feedback) - Webpack (gzipped)	31.33 KB (0%)
@sentry/browser (incl. sendFeedback) - Webpack (gzipped)	31.34 KB (0%)
@sentry/browser - Webpack (gzipped)	22.6 KB (0%)
@sentry/browser (incl. Tracing, Replay, Feedback) - ES6 CDN Bundle (gzipped)	76.04 KB (+0.1% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	67.58 KB (+0.1% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	33.43 KB (+0.09% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped)	24.62 KB (0%)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	213.24 KB (+0.13% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	101.26 KB (+0.26% 🔺)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	73.89 KB (0%)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	36.57 KB (+0.14% 🔺)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	69.69 KB (-0.14% 🔽)
@sentry/react - Webpack (gzipped)	22.63 KB (0%)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	86.48 KB (+0.04% 🔺)
@sentry/nextjs Client - Webpack (gzipped)	50.77 KB (+0.04% 🔺)
@sentry-internal/feedback - Webpack (gzipped)	17.21 KB (0%)