[translations] fix translation setter

3 jobs for add_z_translation in 9 minutes and 40 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Style
passed #193805
check_style

00:00:15

 
  Test Library
passed #193806
test:python3.7_stretch_pyqt5

00:04:41

 
  Test Notbooks
passed #193807
test:test-tomoscan-tutorials

00:04:44