ci: Small adaptions to external contributor workflow

[mydea]

This does two things:

1. Pass the author association to the step - we do not use it right now, but it will be logged at least, allowing us to debug this.
2. Include a reference to the merged PR in the PR body.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser	22.29 KB (+0.07% 🔺)
@sentry/browser (incl. Tracing)	33.44 KB (+0.05% 🔺)
@sentry/browser (incl. Tracing, Replay)	69.19 KB (+0.02% 🔺)
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	62.52 KB (+0.02% 🔺)
@sentry/browser (incl. Tracing, Replay with Canvas)	73.25 KB (+0.03% 🔺)
@sentry/browser (incl. Tracing, Replay, Feedback)	85.88 KB (+0.02% 🔺)
@sentry/browser (incl. Tracing, Replay, Feedback, metrics)	87.74 KB (+0.02% 🔺)
@sentry/browser (incl. metrics)	26.58 KB (+0.05% 🔺)
@sentry/browser (incl. Feedback)	38.97 KB (+0.04% 🔺)
@sentry/browser (incl. sendFeedback)	26.92 KB (+0.06% 🔺)
@sentry/browser (incl. FeedbackAsync)	31.53 KB (+0.05% 🔺)
@sentry/react	25.04 KB (+0.08% 🔺)
@sentry/react (incl. Tracing)	36.48 KB (+0.05% 🔺)
@sentry/vue	26.4 KB (+0.05% 🔺)
@sentry/vue (incl. Tracing)	35.3 KB (+0.05% 🔺)
@sentry/svelte	22.43 KB (+0.06% 🔺)
CDN Bundle	23.51 KB (+0.06% 🔺)
CDN Bundle (incl. Tracing)	35.21 KB (+0.05% 🔺)
CDN Bundle (incl. Tracing, Replay)	69.31 KB (+0.03% 🔺)
CDN Bundle (incl. Tracing, Replay, Feedback)	74.5 KB (+0.04% 🔺)
CDN Bundle - uncompressed	69 KB (+0.05% 🔺)
CDN Bundle (incl. Tracing) - uncompressed	104.02 KB (+0.04% 🔺)
CDN Bundle (incl. Tracing, Replay) - uncompressed	214.41 KB (+0.02% 🔺)
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed	227.12 KB (+0.02% 🔺)
@sentry/nextjs (client)	36.36 KB (+0.04% 🔺)
@sentry/sveltekit (client)	34.09 KB (+0.05% 🔺)
@sentry/node	130.86 KB (+0.02% 🔺)
@sentry/node - without tracing	91.88 KB (+0.02% 🔺)
@sentry/aws-serverless	117.04 KB (+0.02% 🔺)