[Feature Flags] Investigate whether flags context should clone/isolate with the current scope

[aliu39]

Description

Applies for server-side SDKs as well. We currently clone the flag buffer whenever the scope forks, but this could cause us to miss useful flags that are evaluated in sub-tasks, before/during the time the error is raised.

[aliu39]

The currently adopted convention is to clone and isolate on new scopes. Closing since there's no planned work to change this