Cannot enter passphrase in pinentry when Korean language is selected

1. Boot Tails
2. Select Korean language in the greeter (한국어)
3. Run whatever operation that opens the pinentry dialog (e.g. gpg --symmetric)
4. Try to type a passphrase

=> no char placeholder (star) is displayed in the passphrase box.

Feature Branch: winterfairy:bugfix/ibus

Original created by @intrigeri on 6206 (Redmine)