Remove duplicate task gettext:po_to_json

It is already run in "bundle exec rake gitlab:assets:compile".

.gitlab-ci.yml

@@ -247,7 +247,6 @@ setup-test-env:
   script:
     - node --version
     - yarn install --frozen-lockfile --cache-folder .yarn-cache
-    - bundle exec rake gettext:po_to_json
     - bundle exec rake gitlab:assets:compile
     - bundle exec ruby -Ispec -e 'require "spec_helper" ; TestEnv.init'
     - scripts/gitaly-test-build # Do not use 'bundle exec' here
@@ -495,7 +494,6 @@ gitlab:assets:compile:
     NO_COMPRESSION: "true"
   script:
     - yarn install --frozen-lockfile --production --cache-folder .yarn-cache
-    - bundle exec rake gettext:po_to_json
     - bundle exec rake gitlab:assets:compile
   artifacts:
     name: webpack-report