UseBranchWithServices leaves the HttpContext with a disposed service provider when the scope finishes

[DJackman123]

When the scope is created in UseBranchWithServices, it changes the context.RequestServices service provider to be the scope's service provider instead then proceeds with the rest of the pipeline. This is fine, but when the scope is done that service provider is disposed and any middleware in the pipeline before the branch will be stuck with a context whose RequestServices is disposed. The code in UseBranchWithServices should restore the old service provider on the way out so this doesn't happen.