Move updating Apollo cache logic to utils
Summary
Abstract updating cache logic to utils to make the components shorter/more readable.
Improvements
Currently in different Design Management components we have a logic to update Apollo Cache after successful mutation. It would be nice to abstract this logic to utils to make the components shorter/more readable. An example could be found in ee/app/assets/javascripts/design_management/components/design_destroyer.vue
Risks
There are no significant risks in this refactor
Involved components
ee/app/assets/javascripts/design_management/components/design_notes/design_discussion.vue
ee/app/assets/javascripts/design_management/pages/design/index.vue
ee/app/assets/javascripts/design_management/pages/index.vue