fix(capture): Always update stored person props from $set

[Twixes]

Changes

@simfish85 brought to my attention that every posthog.people.set() call fires an event, and I realized this can't quite be optimized away just by using the $set property in posthog.capture()'d events. That's because in the latter case, stored person properties don't get updated, potentially messing up feature flags.

This PR adds the handling around stored person props that posthog-people had to posthog-core. Let me know if this makes sense, I've not been involved in posthog-js lately.

Checklist

• Tests for new code (see advice on the tests we use)
• Accounted for the impact of any changes across different browsers

[github-actions]

Size Change: +665 B (0%)

Total Size: 724 kB

Filename	Size	Change
dist/array.full.js	177 kB	+167 B (0%)
dist/array.js	119 kB	+166 B (0%)
dist/es.js	118 kB	+166 B (0%)
dist/module.js	118 kB	+166 B (0%)

ℹ️ View Unchanged

Filename	Size
dist/recorder-v2.js	95 kB
dist/recorder.js	58.3 kB
dist/surveys.js	38.7 kB

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[neilkakkar]

Makes sense!

Is your plan to aggregate lots of set calls into a capture call to reduce no. of times it sends an event?

[Twixes]

I thought about it, but gonna leave it at this for now. Just so that as a customer you can use either way of $setting and be sure both will work.