Fix repository export to support file columns [SCI-2079]

app/controllers/repositories_controller.rb

@@ -388,7 +388,7 @@ class RepositoriesController < ApplicationController
                      else
                        cell = row.repository_cells
                                  .find_by(repository_column_id: c_id)
-                       cell ? cell.value.data : nil
+                       cell ? cell.value.formatted : nil
                      end
         end
         csv << csv_row

app/models/repository_asset_value.rb

@@ -18,4 +18,8 @@ class RepositoryAssetValue < ApplicationRecord
   def formatted
     asset.file_file_name
   end
+
+  def data
+    asset.file_file_name
+  end
 end