po: fix duplicated de_DE language

See issue #414 and !498
8 jobs for 412-add-german-translation-for-chatty-to-repo in 13 minutes and 21 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Build
passed #301621
librem5
build-debian-gcc-bullseye

00:01:51

passed #301620
librem5
build-debian-gcc-buster

00:01:39

 
  Test
passed #301623
librem5
check-po

00:00:21

passed #301622
librem5
test:debian-gcc

00:01:18

16.8%
 
  Package
passed #301624
librem5
package:deb-debian-buster

00:01:29

passed #301625
librem5:arm64
package:deb-debian-buster:arm64

00:07:32

 
  Test Package
passed #301626
librem5
autopkgtest-debian-buster-package

00:01:08

passed #301627
librem5
lintian-debian-buster-package

00:00:31