Fix Injections clashing with computeds

We have a number of Vue.js components where we have injects clashing with computeds. This needs to be fixed

Offenders:

• app/assets/javascripts/admin/broadcast_messages/components/message_form.vue
• ee/app/assets/javascripts/security_dashboard/components/pipeline/security_dashboard_vuex.vue
• app/assets/javascripts/projects/new/components/new_project_url_select.vue
• app/assets/javascripts/projects/commit/components/form_modal.vue
• app/assets/javascripts/admin/broadcast_messages/components/message_form.vue