Show Progress percentage in rollup data

...ts/javascripts/work_items/components/work_item_detail.vue

...s/components/work_item_links/work_item_rolled_up_data.vue

.../work_items/components/work_item_links/work_item_tree.vue

app/assets/javascripts/work_items/graphql/cache_utils.js

...pts/work_items/graphql/work_item_widgets.fragment.graphql

...mponents/work_item_links/work_item_rolled_up_data_spec.js

locale/gitlab.pot

...k_items/components/work_item_links/work_item_tree_spec.js

spec/frontend/work_items/mock_data.js