Make whole labels translatable in DistributionChoiceForm.
Make whole labels translatable in DistributionChoiceForm.

This makes it easier for translators to choose the correct ordering of
things, e.g for rtl languages and others.

Fixes #3828

mozilla/olympia,atiqueahmedziad/addons-server,harry-7/addons-server,mstriemer/olympia,eviljeff/olympia,lavish205/olympia,mstriemer/addons-server,harikishen/addons-server,mstriemer/olympia,mstriemer/addons-server,diox/olympia,harry-7/addons-server,wagnerand/addons-server,atiqueahmedziad/addons-server,atiqueahmedziad/addons-server,eviljeff/olympia,harry-7/addons-server,harikishen/addons-server,bqbn/addons-server,tsl143/addons-server,wagnerand/olympia,kumar303/addons-server,Revanth47/addons-server,psiinon/addons-server,mozilla/addons-server,mstriemer/addons-server,diox/olympia,kumar303/addons-server,mozilla/addons-server,tsl143/addons-server,kumar303/olympia,Revanth47/addons-server,psiinon/addons-server,lavish205/olympia,eviljeff/olympia,diox/olympia,atiqueahmedziad/addons-server,diox/olympia,psiinon/addons-server,mozilla/addons-server,aviarypl/mozilla-l10n-addons-server,kumar303/olympia,psiinon/addons-server,aviarypl/mozilla-l10n-addons-server,mozilla/olympia,bqbn/addons-server,wagnerand/olympia,aviarypl/mozilla-l10n-addons-server,mstriemer/olympia,wagnerand/olympia,lavish205/olympia,Revanth47/addons-server,kumar303/addons-server,wagnerand/addons-server,eviljeff/olympia,mozilla/addons-server,tsl143/addons-server,wagnerand/olympia,kumar303/olympia,mstriemer/olympia,bqbn/addons-server,kumar303/addons-server,harikishen/addons-server,mozilla/olympia,mozilla/olympia,kumar303/olympia,aviarypl/mozilla-l10n-addons-server,harikishen/addons-server,harry-7/addons-server,mstriemer/addons-server,wagnerand/addons-server,lavish205/olympia,wagnerand/addons-server,bqbn/addons-server,tsl143/addons-server,Revanth47/addons-server