Rebootstrap VMR to use updated Arcade SDK with SignCheck changes

[ellahathaway]

Once all the fixes to SignCheck have been merged and flowed into the VMR, the VMR should be rebootstrapped so that a newer version of the Arcade SDK with the SignCheck changes is used by the VMR signing validation.

[ViktorHofer]

@ellahathaway I assume this can be closed now?

[ellahathaway]

Not quite. I still have to fix the .js verification on .NET Core: #5001. Once those changes flow in, another rebootstrap will be required.

[ellahathaway]

Waiting on a build that includes dotnet/dotnet@761728c