Add ability to change environment after initialisation

[JamesW-iOS]

We've recently integrated the SDK into our iOS app. One issue we've encountered is that we don't seem to be able to update the environment after the reporter is built. Our app has the ability to change region at runtime and we use different Splunk environments for the different regions.

I have attempted to do this by updating the global attribute environment but this doesn't seem to affect which environment the events are logged in. This is the call we're making

SplunkRum.setGlobalAttributes(["environment": [OUR_ENVIRONMENT_NAME]])

Would be really useful if there was a way to update this at runtime or if there is a way and I'm just holding it wrong. Thanks.