uploads: don't delete files of abandoned uploads.

Just leave them. They don't take up that much space and they may be used
in the future if someone else tries to upload the same file.

app/models/upload.rb

@@ -75,8 +75,6 @@ class Upload < ApplicationRecord
   validates_with FileValidator, on: :file
   serialize :context, JSON
 
-  after_destroy_commit :delete_files
-
   scope :pending, -> { where(status: "pending") }
   scope :preprocessed, -> { where(status: "preprocessed") }
   scope :completed, -> { where(status: "completed") }
@@ -104,19 +102,6 @@ class Upload < ApplicationRecord
     end
   end
 
-  concerning :FileMethods do
-    def delete_files
-      # md5 is blank if the upload errored out before downloading the file.
-      if is_completed? || md5.blank? || Upload.exists?(md5: md5) || Post.exists?(md5: md5)
-        return
-      end
-
-      media_asset&.destroy!
-      media_asset&.delete_files!
-      DanbooruLogger.info("Uploads: Deleting files for upload md5=#{md5}")
-    end
-  end
-
   concerning :StatusMethods do
     def is_pending?
       status == "pending"