Wiki events for update and delete do not have icons

Summary

Wiki events in activity streams do not have icons when their action is Event::UPDATED or Event::DESTROYED. See:

This is pretty minor, but we should probably have UX let us know what this should look like.

Steps to reproduce

Update/delete wiki pages, then view the activity stream

Example Project

https://staging.gitlab.com/alexkalderimis/wiki-events-test/activity

Proposal

For delete events, we will use the Trash can icon:

• svg class="s14"
• URL: https://gitlab.com/gitlab-org/gitlab-svgs/-/blob/master/sprite_icons/remove.svg
• color: rgb(112,112,112)

For update events, we will use the Pencil icon:

• svg class="s14"
• URL: https://gitlab.com/gitlab-org/gitlab-svgs/-/blob/master/sprite_icons/pencil.svg
• color: rgb(27,85,102)