fix(android): declare namespace / buildconfig options for gradle plugin 8+ compatibility

[ivanignatiev]

Change is required as per announce in community: react-native-community/discussions-and-proposals#671

Fixes #328

[CLAassistant]

All committers have signed the CLA.

[OHHAKO]

@ivanignatiev hi, thanks for fixing it! you specified the agp version. but why?
I contributed to another repository, but didn't use the terms like you. Because of course I didn't know it was necessary.

def agpVersion = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION
if (agpVersion.tokenize('.')[0].toInteger() >= 7)

[ivanignatiev]

@OHHAKO hi !

I am not sure that it is really really necessary (I am not Java/Grandle expert). Before React Native requirements upgrades, the namespace was taken from AndroidManifest.xml.

For me, it is just a safe formula for backward compatibility for guys who will use the module with older versions of React Native.

[mikehardy]

The reason to specify the version is so that react-native less than 0.66 still works, as it uses gradle < 7 and gradle < 7 does not know about the namespace or buildconfig stuff

So this is a great change. Thanks for your patience! Just now getting to working on my main work app to check it for compatibility (which uses this module, and drives my interest in maintaining this module...)

[mikehardy]

After updating the example app + CI so things would actually build, I pulled this and ran it locally, and it works fine.
CI will check it after a merge to main as well