Retry ListImport rows when they're not unique

(Fixes SERVER-CH1)

app/models/list_import.rb

@@ -42,12 +42,14 @@ def apply
     Chewy.strategy(:atomic) do
       each_with_index do |(media, data), index|
         next if media.blank?
-        # Merge the library entries
-        le = LibraryEntry.where(user_id: user.id, media:).first_or_initialize
-        le.imported = true
-        le = merged_entry(le, data)
-        le.save! unless le.status.nil?
-        yield({ status: :running, total:, progress: index + 1 })
+        Retriable.retriable on: [ActiveRecord::RecordNotUnique] do
+          # Merge the library entries
+          le = LibraryEntry.where(user_id: user.id, media:).first_or_initialize
+          le.imported = true
+          le = merged_entry(le, data)
+          le.save! unless le.status.nil?
+          yield({ status: :running, total:, progress: index + 1 })
+        end
       rescue StandardError => e
         Sentry.capture_exception(e)
         yield({