meta(changelog): Update changelog for 10.12.0

[andreiborza]

The previous branch did not have the correct heading for the release in the changelog so the release preparation failed: https://github.com/getsentry/sentry-javascript/actions/runs/17767168415/job/50493360949#step:7:494

[github-actions]

size-limit report 📦

Path	Size	% Change	Change
@sentry/browser	24.16 kB	added	added
@sentry/browser - with treeshaking flags	22.72 kB	added	added
@sentry/browser (incl. Tracing)	40.16 kB	added	added
@sentry/browser (incl. Tracing, Replay)	78.53 kB	added	added
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	68.24 kB	added	added
@sentry/browser (incl. Tracing, Replay with Canvas)	83.19 kB	added	added
@sentry/browser (incl. Tracing, Replay, Feedback)	95.4 kB	added	added
@sentry/browser (incl. Feedback)	40.87 kB	added	added
@sentry/browser (incl. sendFeedback)	28.81 kB	added	added
@sentry/browser (incl. FeedbackAsync)	33.75 kB	added	added
@sentry/react	25.88 kB	added	added
@sentry/react (incl. Tracing)	42.16 kB	added	added
@sentry/vue	28.64 kB	added	added
@sentry/vue (incl. Tracing)	41.98 kB	added	added
@sentry/svelte	24.19 kB	added	added
CDN Bundle	25.74 kB	added	added
CDN Bundle (incl. Tracing)	40.05 kB	added	added
CDN Bundle (incl. Tracing, Replay)	76.27 kB	added	added
CDN Bundle (incl. Tracing, Replay, Feedback)	81.78 kB	added	added
CDN Bundle - uncompressed	75.18 kB	added	added
CDN Bundle (incl. Tracing) - uncompressed	118.5 kB	added	added
CDN Bundle (incl. Tracing, Replay) - uncompressed	233.6 kB	added	added
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed	246.37 kB	added	added
@sentry/nextjs (client)	44.15 kB	added	added
@sentry/sveltekit (client)	40.6 kB	added	added
@sentry/node-core	49.86 kB	added	added
@sentry/node	151.14 kB	added	added
@sentry/node - without tracing	91.75 kB	added	added
@sentry/aws-serverless	105.19 kB	added	added