Refactor comments presenter to a view component

We've decided to use view components in favor of presenters.

Fixes #11559

src/api/app/components/comment_component.rb

@@ -0,0 +1,31 @@
+class CommentComponent < ApplicationComponent
+  def initialize(comment:, obj_is_user:, builder:)
+    super
+
+    @comment = comment
+    @obj_is_user = obj_is_user
+    @builder = builder
+  end
+
+  def user?
+    @obj_is_user
+  end
+
+  def attributes
+    attrs = { who: comment.user.login, when: comment.created_at, id: comment.id }
+    if user?
+      attrs[comment.commentable.class.name.downcase.to_sym] = comment.commentable.to_param
+      attrs[:project] = comment.commentable.project if comment.commentable.is_a?(Package)
+    end
+    attrs[:parent] = comment.parent_id if comment.parent_id
+    attrs
+  end
+
+  def body
+    comment.body.delete("\u0000")
+  end
+
+  private
+
+  attr_accessor :comment
+end

src/api/app/components/comment_component.xml.builder

@@ -0,0 +1,3 @@
+@builder.comment_(attributes) do
+  @builder.text(body)
+end

src/api/app/views/comments/index.xml.builder

@@ -1,4 +1,3 @@
 xml.comments(@header) do
-  render(partial: 'comment', collection: @comments, locals: { obj_is_user: @obj.is_a?(User),
-                                                              builder: xml })
+  render(CommentComponent.with_collection(@comments, obj_is_user: @obj.is_a?(User), builder: xml))
 end