v4.30.0 - Improve initialize metadata apis

Trigger the initCompletionCallback from setInitializeValues - used when synchronously intiializing the SDK. Also prefers performance.now() when available in the browser to Date.now() for measuring the time returned in initCompletionCallback

Adds the Statsig.initializeCalled() as a convenience method so you can check if you have previously called initialize. Note that waiting for the initialize promise to resolve is still the proper way to wait for initialization

Internal updates:

send event log failure telemetry to a different endpoint for better redundancy.
update eval reason when cached values are up to date
dont rotate session id on update user