fix(utils): Make xhr instrumentation independent of parallel running SDK versions

[lforst]

Fixes #7783

XHR instrumentations of multiple parallel running SDK versions were clashing. We now instead use a field that should be bumped every time we change the layout of the type in a non-backwards compatible way.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	20.98 KB (+0.02% 🔺)
@sentry/browser - ES5 CDN Bundle (minified)	65.55 KB (-0.03% 🔽)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	19.53 KB (+0.02% 🔺)
@sentry/browser - ES6 CDN Bundle (minified)	57.99 KB (-0.02% 🔽)
@sentry/browser - Webpack (gzipped + minified)	21.13 KB (-0.03% 🔽)
@sentry/browser - Webpack (minified)	68.95 KB (-0.02% 🔽)
@sentry/react - Webpack (gzipped + minified)	21.15 KB (-0.03% 🔽)
@sentry/nextjs Client - Webpack (gzipped + minified)	49 KB (+0.12% 🔺)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	28.55 KB (+0.04% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	26.78 KB (+0.05% 🔺)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	44.92 KB (-0.02% 🔽)
@sentry/replay - Webpack (gzipped + minified)	38.88 KB (+0.06% 🔺)
@sentry/browser + @sentry/tracing + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	63.84 KB (+0.04% 🔺)
@sentry/browser + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	56.86 KB (+0.01% 🔺)