Support Statsig experiments (in addition to feature flags)

[danbeam]

Problem Statement

https://www.statsig.com/featureflags are already supported by https://docs.sentry.io/platforms/javascript/configuration/integrations/statsig/

But what about https://www.statsig.com/experimentation?

Solution Brainstorm

Find some way to set experiment metadata on reports/spans.

<experiment_name>:<assigned_group_name> could be one way, but it omits some of the dynamic values. It's similar to <feature_flag>:<true/false> and searchable though (AFAICT).

Additional Context

No response

Priority

No response

[linear-code]

JS-2998

[chargome]

Hey @danbeam thanks for reaching out. I took a quick look at this feature and I think it makes sense to have support for this. I saw that you have opened a PR for this - we'll take it from there!