Migrate from `deprecated_project_avatar/default.vue` to `project_avatar.vue` in `ee/app/assets/javascripts/approvals/components/approvers_list_item.vue`

Description

ee/app/assets/javascripts/approvals/components/approvers_list_item.vue is using vue_shared/components/deprecated_project_avatar/default.vue to render one or more project avatars.

This component is deprecated, and should be replaced with vue_shared/components/project_avatar.vue.

This issue is part of &6295 (closed), an effort to replace vue_shared/components/deprecated_project_avatar/default.vue with vue_shared/components/project_avatar.vue.

Checklist

• Check the rendered component in the browser
• Update the corresponding spec file: ee/spec/frontend/approvals/components/approvers_list_item_spec.js
• Check that the size prop is a valid size
  • If the size needs to be changed, mention this to the UX reviewer

Tips and tricks

• Instead of passing a single project prop, pass projectName and projectAvatarUrl instead
• See this MR !65747 (merged) for an example, and &6295 (closed) for extra info