Bug Template

Title: Remove first then add when adding a scope which has the same key as a to-be-deleted scope.

Description:

A new scope may have the same scope key as a to-be-deleted existing scope, in which case we should not raise an scope key conflict error.

Repro steps:
push -1: { scope A: keyA }
push -2: { Scope B: keyA } (in StoW API, this means deletion of "Scope A").
now in the delta form onConfigUpdate, we will report conflict error as the new scopeB 's "keyA" conflicts with the existing scopeA's key.