feat(core): Deprecate span.getTraceContext()

[mydea]

Instead, you can use a new spanToTraceContext(span) util function.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay, Feedback) - Webpack (gzipped)	76.07 KB (+0.05% 🔺)
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	67.46 KB (+0.09% 🔺)
@sentry/browser (incl. Tracing, Replay) - Webpack with treeshaking flags (gzipped)	61.07 KB (+0.09% 🔺)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	32.04 KB (+0.21% 🔺)
@sentry/browser (incl. Feedback) - Webpack (gzipped)	30.46 KB (+0.13% 🔺)
@sentry/browser - Webpack (gzipped)	22.17 KB (+0.23% 🔺)
@sentry/browser (incl. Tracing, Replay, Feedback) - ES6 CDN Bundle (gzipped)	73.47 KB (+0.06% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	65.13 KB (+0.05% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	31.3 KB (+0.1% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped)	23.22 KB (+0.28% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	204.19 KB (-0.02% 🔽)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	94.08 KB (-0.03% 🔽)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	68.94 KB (+0.3% 🔺)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	34.27 KB (+0.13% 🔺)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	67.87 KB (+0.1% 🔺)
@sentry/react - Webpack (gzipped)	22.19 KB (+0.18% 🔺)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	84.49 KB (+0.04% 🔺)
@sentry/nextjs Client - Webpack (gzipped)	49.1 KB (+0.05% 🔺)
@sentry-internal/feedback - Webpack (gzipped)	16.69 KB (+0.35% 🔺)