fix(core): Only call applyDebugMetadata for error events

[lforst]

We're calling this function for transactions right now which doesn't make sense at all and actually is very performance heavy for people that have debug IDs configured.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	20.94 KB (+0.02% 🔺)
@sentry/browser - ES5 CDN Bundle (minified)	65.46 KB (+0.03% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	19.5 KB (+0.04% 🔺)
@sentry/browser - ES6 CDN Bundle (minified)	57.9 KB (+0.03% 🔺)
@sentry/browser - Webpack (gzipped + minified)	21.1 KB (+0.04% 🔺)
@sentry/browser - Webpack (minified)	68.85 KB (+0.03% 🔺)
@sentry/react - Webpack (gzipped + minified)	21.13 KB (+0.04% 🔺)
@sentry/nextjs Client - Webpack (gzipped + minified)	48.9 KB (+0.02% 🔺)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	28.5 KB (+0.02% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	26.74 KB (+0.03% 🔺)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	44.89 KB (+0.02% 🔺)
@sentry/replay - Webpack (gzipped + minified)	38.85 KB (0%)
@sentry/browser + @sentry/tracing + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	63.79 KB (+0.01% 🔺)
@sentry/browser + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	56.82 KB (+0.02% 🔺)