Extract component to render avatars in comments

This way it'll be easier to add tests for it and refactor it.

spec/components/comments/avatar_component_spec.rb

@@ -0,0 +1,56 @@
+require "rails_helper"
+
+describe Comments::AvatarComponent do
+  it "displays a regular avatar for regular comments" do
+    comment = create(:comment, user: create(:user, username: "Oscar Wilde"))
+
+    render_inline Comments::AvatarComponent.new(comment)
+
+    expect(page).to have_avatar "O"
+    expect(page).not_to have_css "img"
+  end
+
+  it "displays the admin avatar for admin comments" do
+    admin = create(:administrator)
+    comment = create(:comment, user: admin.user, administrator_id: admin.id)
+
+    render_inline Comments::AvatarComponent.new(comment)
+
+    expect(page).to have_css "img.admin-avatar"
+  end
+
+  it "displays the moderator avatar for moderator comments" do
+    moderator = create(:moderator)
+    comment = create(:comment, user: moderator.user, moderator_id: moderator.id)
+
+    render_inline Comments::AvatarComponent.new(comment)
+
+    expect(page).to have_css "img.moderator-avatar"
+  end
+
+  it "displays the organization avatar for organization comments" do
+    comment = create(:comment, user: create(:organization).user)
+
+    render_inline Comments::AvatarComponent.new(comment)
+
+    expect(page).to have_css "img.avatar"
+  end
+
+  it "displays an empty icon for comments by hidden users" do
+    comment = create(:comment, user: create(:user, :hidden))
+
+    render_inline Comments::AvatarComponent.new(comment)
+
+    expect(page).to have_css ".user-deleted"
+    expect(page).not_to have_css "img"
+  end
+
+  it "displays an empty icon for comments by erased users" do
+    comment = create(:comment, user: create(:user, erased_at: Time.current))
+
+    render_inline Comments::AvatarComponent.new(comment)
+
+    expect(page).to have_css ".user-deleted"
+    expect(page).not_to have_css "img"
+  end
+end