feat: allow android plugins to have cpp code

PR Checklist

[ ] The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/tools/notes/CONTRIBUTING.md#commit-messages.
[ ] There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
[ ] You have signed the CLA.
[ ] All existing tests are passing: https://github.com/NativeScript/nativescript-cli/blob/master/CONTRIBUTING.md#contribute-to-the-code-base
[ ] Tests for the changes are included.

Fixes/Implements/Closes #[Issue Number].