feat(core): add support for Experiments in Statsig Integration

[danbeam]

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Meant to start a conversation around #22170 (and mildly related to #21157)

[chargome]

Hey @danbeam thanks again for the contribution! Non-boolean values for features will not be supported atm, so for the time being this will not make it into the integration. Good news is that you can easily add any value as attributes to your telemetry via attributes and then query against this. I will leave your issue open though to track community signals for this feature!