fix when author is missing on import

app/models/communication/website/imported/post.rb

@@ -101,7 +101,7 @@ class Communication::Website::Imported::Post < ApplicationRecord
     post.published = true
 
     imported_author = website.authors.where(identifier: author).first
-    post.author = imported_author.author if imported_author.author
+    post.author = imported_author.author if imported_author&.author.present?
     imported_categories = website.categories.where(identifier: categories)
     imported_categories.each do |imported_category|
       post.categories << imported_category.category unless post.categories.pluck(:id).include?(imported_category.category_id)