Remove implementation details from i18n hidden api flags am: d66e1e13fb am: 8b5d456f1a am: bc61ffe7ca

Original change: https://android-review.googlesource.com/c/platform/packages/modules/RuntimeI18n/+/2026764

Change-Id: I031d0e3751ccc5055db88ea85cd6eb491b2f1fb8