Fix configuration/resource handling in activity contexts

[copybara-service]

Fix configuration/resource handling in activity contexts

A few fixes to address correct behavior of configuration and resources when using activity contexts:

• Create the activity token before creating the activity context and correctly pass it in instead of passing in the null token from the base context, this is necessary as the context uses the token to key resources so using a null token results in activities using incorrect asset managers
• Pass through a correct override config when creating the activity context, most of the time the override config can safely be null and just inherit from the application but when explicitly configuring resources on an activity during configuration change we should pass in the request override
• Trigger activity configuration change for ActivityScenario (i.e. those created by the instrumentation) activities based on the application resources changing configuration rather than the static system ones, applications generally expect the application configuration to be consistent with the activity resources and RuntimeEnvironment is configuring the application resource configurations after the system ones so triggering on the system ones was too early.