ref(eap-outcomes): use sentry-options to change which timestamp to use

[kenzoengineer]

This is a duplicate of #7834, using sentry-options instead of the old config method.

#7836 should be merged first to ensure all the scaffolding works in production.

Because this is a duplicate, the logic, usage, and tests all mirror #7834. The only thing I've added is we use sentry-options instead.

[kenzoengineer]

added this extra test to make sure toggling it actually does something

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[kenzoengineer]

@MeredithAnya @onewland

and cc @hubertdeng123

init(), options() and .get() now all return an Err and won't panic. However, I made an explicit decision in this PR to have all of them panic (fail loudly) when there is an error. You two are owners of this code so I wanted to see what you guys thought about that, and whether you want to gracefully handle anything?