Re-added ambiguous Automation ctor that was removed in CL2605826. It is now marked with [Obsolete], and will be removed in the future. CL2643334 already fixed the instances that were mistakenly being routed to the varargs version.
#codereview:richard.fawcett, leigh.swift, ben.marsh
[CL 2643482 by Wes Hunt in Main branch]