fix(tracing): Guard against missing window.location

[mydea]

We should also backport this to v7, probably.

Closes #10578

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay, Feedback) - Webpack (gzipped)	77.82 KB (0%)
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	69.06 KB (0%)
@sentry/browser (incl. Tracing, Replay with Canvas) - Webpack (gzipped)	72.98 KB (0%)
@sentry/browser (incl. Tracing, Replay) - Webpack with treeshaking flags (gzipped)	62.67 KB (0%)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	33.25 KB (0%)
@sentry/browser (incl. browserTracingIntegration) - Webpack (gzipped)	33.16 KB (+0.05% 🔺)
@sentry/browser (incl. Feedback) - Webpack (gzipped)	31.16 KB (0%)
@sentry/browser (incl. sendFeedback) - Webpack (gzipped)	31.16 KB (0%)
@sentry/browser - Webpack (gzipped)	22.43 KB (0%)
@sentry/browser (incl. Tracing, Replay, Feedback) - ES6 CDN Bundle (gzipped)	76.11 KB (+0.02% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	67.64 KB (+0.06% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	33.6 KB (+0.05% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped)	24.71 KB (+0.06% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	212.88 KB (+0.04% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	101.5 KB (+0.07% 🔺)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	74.01 KB (+0.09% 🔺)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	36.83 KB (+0.04% 🔺)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	69.43 KB (0%)
@sentry/react - Webpack (gzipped)	22.45 KB (0%)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	87.1 KB (+0.02% 🔺)
@sentry/nextjs Client - Webpack (gzipped)	50.36 KB (+0.02% 🔺)
@sentry-internal/feedback - Webpack (gzipped)	17.12 KB (0%)