fix(android): Add Tamil lexical model to KMSample2

Cherrypick of #3123 to stable-13.0

2 additional changes:
* stable-13.0   copies the model asset files instead of installing example.ta.wordlist.model.kmp
* Add node_modules to top level .gitignore (to reduce the diffs when developers switch between 14.0 and stable-13.0)