DEV: Remove reference to very old plugin (#13098)

lib/plugin/instance.rb

@@ -86,10 +86,6 @@ class Plugin::Instance
     [].tap { |plugins|
       # also follows symlinks - http://stackoverflow.com/q/357754
       Dir["#{parent_path}/*/plugin.rb"].sort.each do |path|
-
-        # tagging is included in core, so don't load it
-        next if path =~ /discourse-tagging/
-
         source = File.read(path)
         metadata = Plugin::Metadata.parse(source)
         plugins << self.new(metadata, path)