[workload] Allow installation on linux-arm64 (#8500)

We currently do not allow installation of the `android` workload on
linux-arm64, but suspect that it may work for some customers.  Given
that our [runtime dependencies][0] are now available for linux-arm64,
we can stop restricting installation to solicit feedback.

[0]: https://github.com/dotnet/runtime/blob/087ca4662309f3db40b3096cbf89853d9c292e16/src/mono/nuget/Microsoft.NET.Workload.Mono.Toolchain.net8.Manifest/WorkloadManifest.json.in#L44

src/Xamarin.Android.Build.Tasks/Microsoft.NET.Sdk.Android/WorkloadManifest.in.json

@@ -13,7 +13,7 @@
         "Microsoft.Android.Runtime.34.android-x64",
         "Microsoft.Android.Templates"
       ],
-      "platforms": [ "win-x64", "win-arm64", "linux-x64", "osx-x64", "osx-arm64" ],
+      "platforms": [ "win-x64", "win-arm64", "linux-x64", "linux-arm64", "osx-x64", "osx-arm64" ],
       "extends" : [ 
         "microsoft-net-runtime-android-net7",
         "microsoft-net-runtime-android-aot-net7",
@@ -32,7 +32,8 @@
         "win-x86": "Microsoft.Android.Sdk.Windows",
         "win-x64": "Microsoft.Android.Sdk.Windows",
         "win-arm64": "Microsoft.Android.Sdk.Windows",
-        "linux-x64": "Microsoft.Android.Sdk.Linux"
+        "linux-x64": "Microsoft.Android.Sdk.Linux",
+        "linux-arm64": "Microsoft.Android.Sdk.Linux"
       }
     },
     "Microsoft.Android.Sdk.net7": {
@@ -44,7 +45,8 @@
         "win-x86": "Microsoft.Android.Sdk.Windows",
         "win-x64": "Microsoft.Android.Sdk.Windows",
         "win-arm64": "Microsoft.Android.Sdk.Windows",
-        "linux-x64": "Microsoft.Android.Sdk.Linux"
+        "linux-x64": "Microsoft.Android.Sdk.Linux",
+        "linux-arm64": "Microsoft.Android.Sdk.Linux"
       }
     },
     "Microsoft.Android.Ref.34": {