en.json carries ~190 keys per locale that the locale catalogs have not been
bootstrapped with yet, so every repair-locale-catalog run threw a TypeError
before doing any work. Skip missing leaves instead.
Split out of #11728 so the crash fix can land without the catalog
regeneration, which still needs native-speaker review.
Co-authored-by: Turtle-Hwan <turtlehwan@gmail.com>
Co-authored-by: Orca <help@stably.ai>