views: remove tag size indicator bars from /tags.

Remove tag size indicator bars. These bars don't play nicely with dark
mode and aren't all that useful to begin with.

app/helpers/tags_helper.rb

@@ -37,10 +37,4 @@ module TagsHelper
 
     html.html_safe
   end
-  
-  def tag_post_count_style(tag)
-    @highest_post_count ||= Tag.highest_post_count
-    width_percent = Math.log([tag.post_count, 1].max, @highest_post_count) * 100
-    "background: linear-gradient(to left, #DDD #{width_percent}%, white #{width_percent}%)"
-  end
 end