feat(core): Decouple scope.transactionName from root spans

[Lms24]

This PR makes some changes to how we apply scope data to events. Previously, we used to apply the transaction name

1. from scopeData.transactionName
2. if not already set in 1) the name of the root span

to the event.transaction field.

With our efforts to decouple the scope's transaction field from a currently active transaction/root span, we now change this behaviour so that:

• only non-transaction events are assigned event.transaction from scopeData.transactionName (e.g. errors, profiles, replay)
• only transaction events are assigned event.transaction from the root span name

Furthermore, this PR also undeprecates ScopeData.transactionName as we'll still need it.

ref #10846

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay, Feedback) - Webpack (gzipped)	76.98 KB (+0.01% 🔺)
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	68.24 KB (+0.01% 🔺)
@sentry/browser (incl. Tracing, Replay with Canvas) - Webpack (gzipped)	72.12 KB (+0.01% 🔺)
@sentry/browser (incl. Tracing, Replay) - Webpack with treeshaking flags (gzipped)	61.79 KB (+0.01% 🔺)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	32.44 KB (+0.03% 🔺)
@sentry/browser (incl. browserTracingIntegration) - Webpack (gzipped)	32.44 KB (+0.03% 🔺)
@sentry/browser (incl. Feedback) - Webpack (gzipped)	31.37 KB (+0.02% 🔺)
@sentry/browser (incl. sendFeedback) - Webpack (gzipped)	31.37 KB (+0.02% 🔺)
@sentry/browser - Webpack (gzipped)	22.56 KB (+0.02% 🔺)
@sentry/browser (incl. Tracing, Replay, Feedback) - CDN Bundle (gzipped)	75.08 KB (+0.02% 🔺)
@sentry/browser (incl. Tracing, Replay) - CDN Bundle (gzipped)	66.69 KB (+0.02% 🔺)
@sentry/browser (incl. Tracing) - CDN Bundle (gzipped)	32.54 KB (+0.04% 🔺)
@sentry/browser - CDN Bundle (gzipped)	24.02 KB (+0.06% 🔺)
@sentry/browser (incl. Tracing, Replay) - CDN Bundle (minified & uncompressed)	209.07 KB (+0.03% 🔺)
@sentry/browser (incl. Tracing) - CDN Bundle (minified & uncompressed)	97.87 KB (+0.05% 🔺)
@sentry/browser - CDN Bundle (minified & uncompressed)	71.77 KB (+0.07% 🔺)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	68.44 KB (+0.01% 🔺)
@sentry/react - Webpack (gzipped)	22.59 KB (+0.04% 🔺)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	84.95 KB (+0.01% 🔺)
@sentry/nextjs Client - Webpack (gzipped)	49.35 KB (+0.03% 🔺)
@sentry-internal/feedback - Webpack (gzipped)	17.42 KB (+0.07% 🔺)

[mydea]

👍 good comment!

[mydea]

nice! left some small nits but overall looks good to me 👍