feat(web-analytics): Add property for autocapture link click

[robbie-c]

Changes

This PR creates a new property, which is the href when an external link is clicked. External is defined as a different host, and the intention here is for people to measure things like which landing pages lead to which external link clicks.

(I was basically nerd-sniped into adding this by some customer feedback)

We already capture this, but it's very buried inside the $element array, and not always at the same place (not always $elements.0.attr_href), so its hard to add to the sessions MV.

Tested this manually by adding an external link to the nextjs playground, and confirming that I could see the event and property.

Checklist

• Tests for new code (see advice on the tests we use)
• Accounted for the impact of any changes across different browsers
• Accounted for backwards compatibility of any changes (no breaking changes in posthog-js!)

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated (UTC)
posthog-js	✅ Ready (Inspect)	Visit Preview	Jun 21, 2024 11:40am

[github-actions]

Size Change: +64 B (+0.01%)

Total Size: 1.01 MB

Filename	Size	Change
dist/array.full.js	241 kB	+42 B (+0.02%)
dist/array.js	138 kB	+40 B (+0.03%)
dist/es.js	138 kB	+40 B (+0.03%)
dist/module.js	139 kB	+40 B (+0.03%)
dist/surveys-module-previews.js	59.6 kB	-49 B (-0.08%)
dist/surveys.js	61.2 kB	-49 B (-0.08%)

ℹ️ View Unchanged

Filename	Size
dist/exception-autocapture.js	12.2 kB
dist/recorder-v2.js	109 kB
dist/recorder.js	109 kB
dist/tracing-headers.js	8.26 kB

_{compressed-size-action}

[mariusandra]

Found a typo, otherwise looks good. Not 100% convinced of the property name, but got nothing better.