Better sync the value of `MaximumCompatibleNDKMajorVersion` with the one set in xaprepare

[pjcollins]

We should figure out a better way to make sure to keep the max supported NDK version in sync across products.

We bumped xamarin-android to NDK 24 recently in https://github.com/xamarin/xamarin-android/blob/286a20e85da7f28cd138ab86a2b46ae7ab54be4f/build-tools/xaprepare/xaprepare/ConfigAndData/BuildAndroidPlatforms.cs#L8, but forgot to update:
https://github.com/xamarin/xamarin-android-tools/blob/47832f1878e30446eebdafaf1f8b1ac5903bdca9/src/Xamarin.Android.Tools.AndroidSdk/Sdks/AndroidSdkBase.cs#L14