Add link to Android doc (#114977)

* Add link to Android doc

* Update docs/project/os-onboarding.md

Co-authored-by: Jan Kotas <jkotas@microsoft.com>

---------

Co-authored-by: Jan Kotas <jkotas@microsoft.com>

Author: richlander

docs/project/os-onboarding.md

@@ -119,7 +119,9 @@ VMs and raw metal environments are used for Android, Apple, Linux, and Windows O
 
 ### Other
 
-Other environments are typically use a custom process.
+Other environments have their own process.
+
+- [Android](../workflow/testing/libraries/testing-android.md#upgrading-the-android-ndk-version-in-ci-pipelines)
 
 - [Browser Wasm](https://github.com/dotnet/runtime/pull/112066)