Internationalization is broken since Gutenberg moved away from babel-plugin-makepot.

Indeed, build files for each packages in gutenberg is now used as input for glotpress to generate pot files. This means our assumption that mobile native strings in the gutenberg repository will be picked up automatically was wrong.

We need to fix this and either:

1. have gutenberg include our strings
2. include those in our gutenberg-mobile.pot.

Solution 2. is probably more realistic as it will induce less friction with the WordPress core and Gutenberg projects but will bring us one step back in terms of automating translations for gutenberg-mobile.

See related discussions:
https://make.wordpress.org/core/2018/11/09/new-javascript-i18n-support-in-wordpress/
https://make.wordpress.org/core/2018/05/01/javascript-internationalization-the-missing-pieces/
https://wordpress.slack.com/archives/C04KRK0KA/p1525791742000720
https://meta.trac.wordpress.org/ticket/3876