build: Add size-limit entry for metrics

[mydea]

We had no entry covering the bundle size of metrics so far.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser	21.74 KB (0%)
@sentry/browser (incl. Tracing)	32.75 KB (0%)
@sentry/browser (incl. Tracing, Replay)	68.22 KB (0%)
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	61.64 KB (0%)
@sentry/browser (incl. Tracing, Replay with Canvas)	72.27 KB (0%)
@sentry/browser (incl. Tracing, Replay, Feedback)	84.33 KB (0%)
@sentry/browser (incl. Feedback)	37.75 KB (0%)
@sentry/browser (incl. sendFeedback)	26.32 KB (0%)
@sentry/browser (incl. FeedbackAsync)	30.74 KB (0%)
@sentry/react	24.43 KB (0%)
@sentry/react (incl. Tracing)	35.75 KB (0%)
@sentry/vue	25.68 KB (0%)
@sentry/vue (incl. Tracing)	34.56 KB (0%)
@sentry/svelte	21.88 KB (0%)
CDN Bundle	24.28 KB (0%)
CDN Bundle (incl. Tracing)	34.22 KB (0%)
CDN Bundle (incl. Tracing, Replay)	68.04 KB (0%)
CDN Bundle (incl. Tracing, Replay, Feedback)	73.05 KB (0%)
CDN Bundle - uncompressed	71.46 KB (0%)
CDN Bundle (incl. Tracing) - uncompressed	101.58 KB (0%)
CDN Bundle (incl. Tracing, Replay) - uncompressed	211.48 KB (0%)
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed	223.86 KB (0%)
@sentry/nextjs (client)	35.1 KB (0%)
@sentry/sveltekit (client)	33.35 KB (0%)
@sentry/node	114.6 KB (0%)
@sentry/aws-serverless	103.29 KB (0%)
@sentry/browser (incl. Tracing, Replay, Feedback, metrics)	85.8 KB (added)
@sentry/browser (incl. metrics)	23.13 KB (added)