feat(inputs.webhooks.github): Add run_id field to workflow_run events

[warintara]

Summary

Added run_id field to the Telegraf GitHub webhook plugin's workflow_run event parsing.

Changes:

• Added ID int64 to the workflowRun struct to deserialize the id field from the GitHub webhook JSON payload
• Added run_id to the InfluxDB fields map in workflowRunEvent.newMetric() so the value is stored in the database

Why: The GitHub Actions run ID is the unique identifier used in GitHub Action URLs (/actions/runs/<run_id>). Without
storing it, there was no way to build direct links from the Grafana dashboard back to the specific GitHub Actions
run. This change enables linking each row in the dashboard to its corresponding GitHub Actions page.

Checklist

• AI generated code used in this PR follows the InfluxData Policy on AI-Generated Code Contributions

Related issues

resolves #19158

[telegraf-tiger]

Thanks so much for the pull request!
🤝 ✒️ Just a reminder that the CLA has not yet been signed, and we'll need it before merging. Please sign the CLA when you get a chance, then post a comment here saying !signed-cla

[warintara]

!signed-cla

[warintara]

Hello @srebhan @skartikey, could you please take a look at this PR when you have a moment? Let me know if you have any questions or need any clarifications. Thank you!

[skartikey]

plugins/inputs/webhooks/github/README.md:456-459 - the workflow_run event section documents every emitted field (the "Fields:" list at line 454), and the new run_id is missing. Please add it to that list:

* 'run_id' = `event.workflow_run.id` int

[telegraf-tiger]

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Artifact URLs

. DEB	. RPM	. TAR . GZ	. ZIP
amd64.deb	aarch64.rpm	darwin_amd64.tar.gz	windows_amd64.zip
arm64.deb	armel.rpm	darwin_arm64.tar.gz	windows_arm64.zip
armel.deb	armv6hl.rpm	freebsd_amd64.tar.gz	windows_i386.zip
armhf.deb	i386.rpm	freebsd_armv7.tar.gz
i386.deb	ppc64le.rpm	freebsd_i386.tar.gz
mips.deb	riscv64.rpm	linux_amd64.tar.gz
mipsel.deb	s390x.rpm	linux_arm64.tar.gz
ppc64el.deb	x86_64.rpm	linux_armel.tar.gz
riscv64.deb		linux_armhf.tar.gz
s390x.deb		linux_i386.tar.gz
		linux_mips.tar.gz
		linux_mipsel.tar.gz
		linux_ppc64le.tar.gz
		linux_riscv64.tar.gz
		linux_s390x.tar.gz

[warintara]

Done, I have added run_id to the Fields list in the README. Thanks for the feedback! @skartikey