fix: improve ndk home compatibility

[gengjiawen]

The preferred environment variable for specifying the location of the Android NDK is ANDROID_NDK_HOME. NDK_HOME is an older variable that was used in earlier versions of the Android NDK, but it is no longer recommended for use.

[cortinico]

I'm unsure if we need this as NDK_HOME is needed only for Buck compatibility 🤔

[gengjiawen]

I'm unsure if we need this as NDK_HOME is needed only for Buck compatibility 🤔

This in for regular Android NDK developing app without using buck.

[cortinico]

Yup what I'm saying is that this is not correct:

ENV ANDROID_NDK_HOME=${ANDROID_HOME}/ndk/$NDK_VERSION_BUCK

We need NDK_HOME as we have two NDKs. Buck understands only up to NDK 21 so we set NDK_HOME for it. For "regular Android development" the NDK is another one (the 23). Setting ANDROID_NDK_HOME can have unintended side effects as we want Gradle to pickup NDK 23