Refactored work item to coarse-grained subscription

...vascripts/work_items/components/work_item_description.vue

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

...ts/javascripts/work_items/components/work_item_labels.vue

...rk_items/graphql/work_item_assignees.subscription.graphql

..._items/graphql/work_item_description.subscription.graphql

.../work_items/graphql/work_item_labels.subscription.graphql

...rk_items/graphql/work_item_milestone.subscription.graphql

...s/work_items/graphql/work_item_title.subscription.graphql

...work_items/graphql/work_item_updated.subscription.graphql

...scripts/work_items/components/work_item_health_status.vue

...javascripts/work_items/components/work_item_iteration.vue

...ts/javascripts/work_items/components/work_item_weight.vue

...tems/graphql/work_item_health_status.subscription.graphql

...rk_items/graphql/work_item_iteration.subscription.graphql

.../work_items/graphql/work_item_labels.subscription.graphql

...c/frontend/work_items/components/work_item_detail_spec.js

...end/work_items/components/work_item_health_status_spec.js

...rontend/work_items/components/work_item_iteration_spec.js

...c/frontend/work_items/components/work_item_labels_spec.js

...c/frontend/work_items/components/work_item_weight_spec.js