Feature request: support Date objects as traits #329
Description
OpenFeature supports Datetime types for context attributes, but Flagsmith traits do not.
Because of this, the OpenFeature provider has to make a copy of all the traits and map any Date objects into strings, which we've added in open-feature/js-sdk-contrib#1351. The OpenFeature provider could potentially have some smarter logic/caching to avoid this copying, but this is overkill for what should be a simple adapter on top of the Flagsmith SDK.
Ideally, the Flagsmith SDK should natively support Date objects, and only serialise them into strings when needed. This avoids having to make a copy of the entire evaluation context whenever it changes, and makes the OpenFeature provider implementation simpler and faster.