Follow-up from "Adjust approvals table" - table header translations

The following discussion from !142826 (merged) should be addressed:

• @bsandlin started a discussion:

  nitpick (non-blocking): We could add a i18n object in the script and use that here as well as the line above. We could also add other translations while you're at it. I am not sure how extensive you are wanting to get here though. If this is just a quick fix MR feel free to ignore this!

Regarding the other translations in ee/app/assets/javascripts/approvals/components/rules/empty_rule.vue, they should actually be bound to HEADERS in rules.vue, since those are only supportive headers for a collapsed table and should always be matching the original table headers. Current solution sets us for possible differences between mobile and desktop view, if the copy changes in one of the locations.

This problem applies to all :data-label attributes in the following files:

• ee/app/assets/javascripts/approvals/project_settings/project_rules.vue
• ee/app/assets/javascripts/approvals/mr_edit/mr_rules.vue
• ee/app/assets/javascripts/approvals/components/rules/empty_rule.vue