Implement Vertical Build for Android x86 Mono

[mmitche]

This issue covers productization of the following vertical: Android x86 Mono

• Build OS: Mariner
• Target OS: Android
• Build OS Arch: x64
• Target Arch: x86
• Stack Type: Short
• Key Artifacts: Android x86 Mono Runtime Packs

Implementation of this vertical may depend on completion of other items within the Unified Build Space:

• Link issues as necessary

When complete, the following will be true:

• The vertical builds successfully and required changes are backported to individual repos.
• The vertical's outputs are verified as being complete and correct as compared to the current .NET official build.
• The vertical is enabled in VMR rolling CI and PR (if applicable).

T-Shirt Size: Small (default, update as necessary)