Enable build job in aarch64-darwin workflow

Re-enable the build job for aarch64-darwin platform.

Author: angerman

.github/workflows/aarch64-darwin.yml

@@ -5,7 +5,6 @@ on:
 
 jobs:
   build:
-    if: false  # Disabled until macOS hydra builders are back online
     name: Prebuild and Upload
     uses: ./.github/workflows/main.yml
     with: