fix(react): Detect React Router v6/v7 navigations in a layout effect to propagate the correct trace

[chargome]

Fixes React Router v6/v7 propagating the stale pageload trace for requests in route mount effects

closes#21322

[github-actions]

size-limit report 📦

Path	Size	% Change	Change
@sentry/browser	27.2 kB	-	-
@sentry/browser - with treeshaking flags	25.65 kB	-	-
@sentry/browser (incl. Tracing)	45.25 kB	-	-
@sentry/browser (incl. Tracing + Span Streaming)	47.48 kB	-	-
@sentry/browser (incl. Tracing, Profiling)	50.24 kB	-	-
@sentry/browser (incl. Tracing, Replay)	84.87 kB	-	-
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	74.44 kB	-	-
@sentry/browser (incl. Tracing, Replay with Canvas)	89.58 kB	-	-
@sentry/browser (incl. Tracing, Replay, Feedback)	102.2 kB	-	-
@sentry/browser (incl. Feedback)	44.36 kB	-	-
@sentry/browser (incl. sendFeedback)	32.02 kB	-	-
@sentry/browser (incl. FeedbackAsync)	37.11 kB	-	-
@sentry/browser (incl. Metrics)	28.27 kB	-	-
@sentry/browser (incl. Logs)	28.51 kB	-	-
@sentry/browser (incl. Metrics & Logs)	29.22 kB	-	-
@sentry/react	29.03 kB	-	-
@sentry/react (incl. Tracing)	47.58 kB	+0.12%	+53 B 🔺
@sentry/vue	32.22 kB	-	-
@sentry/vue (incl. Tracing)	47.17 kB	-	-
@sentry/svelte	27.23 kB	-	-
CDN Bundle	29.57 kB	-	-
CDN Bundle (incl. Tracing)	47.82 kB	-	-
CDN Bundle (incl. Logs, Metrics)	31.08 kB	-	-
CDN Bundle (incl. Tracing, Logs, Metrics)	49.06 kB	-	-
CDN Bundle (incl. Replay, Logs, Metrics)	70.36 kB	-	-
CDN Bundle (incl. Tracing, Replay)	85.22 kB	-	-
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)	86.39 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback)	91.08 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)	92.23 kB	-	-
CDN Bundle - uncompressed	87.7 kB	-	-
CDN Bundle (incl. Tracing) - uncompressed	144.13 kB	-	-
CDN Bundle (incl. Logs, Metrics) - uncompressed	92.19 kB	-	-
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed	147.88 kB	-	-
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed	217 kB	-	-
CDN Bundle (incl. Tracing, Replay) - uncompressed	262.99 kB	-	-
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed	266.74 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed	276.69 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed	280.42 kB	-	-
@sentry/nextjs (client)	50.05 kB	-	-
@sentry/sveltekit (client)	45.71 kB	-	-
@sentry/core/server	75.94 kB	-	-
@sentry/core/browser	63.09 kB	-	-
@sentry/node-core	61.7 kB	+0.01%	+4 B 🔺
@sentry/node	130.4 kB	-	-
@sentry/node - without tracing	74.06 kB	+0.01%	+2 B 🔺
@sentry/aws-serverless	86.26 kB	-	-
@sentry/cloudflare (withSentry) - minified	171.85 kB	-	-
@sentry/cloudflare (withSentry)	429.49 kB	-	-

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[chargome]

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