feat(core): Update spanToJSON to handle OTEL spans

[mydea]

This is an important step towards aligning OTEL & Sentry Spans 🎉 You can see that the Span interface is now aligned enough that it accepts an OTEL span.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay, Feedback) - Webpack (gzipped)	77.36 KB (+0.28% 🔺)
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	68.57 KB (+0.28% 🔺)
@sentry/browser (incl. Tracing, Replay with Canvas) - Webpack (gzipped)	72.49 KB (+0.25% 🔺)
@sentry/browser (incl. Tracing, Replay) - Webpack with treeshaking flags (gzipped)	62.13 KB (+0.33% 🔺)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	32.83 KB (+0.58% 🔺)
@sentry/browser (incl. browserTracingIntegration) - Webpack (gzipped)	32.83 KB (+0.58% 🔺)
@sentry/browser (incl. Feedback) - Webpack (gzipped)	31.33 KB (+1.06% 🔺)
@sentry/browser (incl. sendFeedback) - Webpack (gzipped)	31.34 KB (+1.07% 🔺)
@sentry/browser - Webpack (gzipped)	22.55 KB (+1.37% 🔺)
@sentry/browser (incl. Tracing, Replay, Feedback) - ES6 CDN Bundle (gzipped)	75.44 KB (+0.19% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	67.1 KB (+0.23% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	32.97 KB (+0.42% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped)	24.06 KB (+1.03% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	210.62 KB (+0.23% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	99.48 KB (+0.48% 🔺)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	71.78 KB (+1.07% 🔺)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	36.08 KB (+0.43% 🔺)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	68.86 KB (+0.29% 🔺)
@sentry/react - Webpack (gzipped)	22.58 KB (+1.39% 🔺)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	85.29 KB (+0.22% 🔺)
@sentry/nextjs Client - Webpack (gzipped)	49.7 KB (+0.4% 🔺)
@sentry-internal/feedback - Webpack (gzipped)	17.4 KB (+1.76% 🔺)