gn2bp: Add Licensing to Android.bp

* This was generated as per http://go/android-license-faq. `scan_project` binary was used to figure out all of the licenses that exist in `external/cronet` then manual filtering for `UNKNOWN` license.

Test: m
Bug: b/263943025
Change-Id: Ia63a694a2245d0b3fa646402e6adf5a7bbaadfe7
2 files changed