chore: Add external contributor to CHANGELOG.md (#25375)

This PR adds the external contributor to the CHANGELOG.md file, so that
they are credited for their contribution. See #25246

Co-authored-by: timfish <1150298+timfish@users.noreply.github.com>

Author: javascript-sdk-gitflow[bot]

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 - "You miss 100 percent of the chances you don't take. — Wayne Gretzky" — Michael Scott
 
+Work in this release was contributed by @kunal649. Thank you for your contribution!
+
 ### Important Changes
 
 - **feat(bundler-plugins): Release `@sentry/webpack-plugin`, `@sentry/vite-plugin`, `@sentry/rollup-plugin` and `@sentry/esbuild-plugin` from the SDK repository ([#25095](https://github.com/getsentry/sentry-javascript/pull/25095))**