Avoid stomping on SatelliteDllsProjectOutputGroupDependsOn (#7962)
Avoid stomping on SatelliteDllsProjectOutputGroupDependsOn (#7962)

The `SatelliteDllsProjectOutputGroupDependsOn` msbuild property is written unconditionally and without regard to its previous value. 
In this change, the targets we require are *appended* to any prior value, thereby making extensibility easier.
rainersigwald/msbuild,rainersigwald/msbuild,rainersigwald/msbuild,rainersigwald/msbuild