fix(campaign): mark excluded delivery as skipped

tests/test_attachment_building.py

@@ -123,6 +123,9 @@ class CampaignAttachmentBuildTests(unittest.TestCase):
                     message = result.report.messages[0]
                     self.assertEqual(message.build_status.value, build_status)
                     self.assertEqual(message.validation_status.value, validation_status)
+                    if validation_status == "excluded":
+                        self.assertEqual(message.send_status.value, "skipped")
+                        self.assertEqual(message.imap_status.value, "skipped")
                     coverage_issues = [issue for issue in message.issues if issue.code == "missing_attachment_coverage"]
                     if issue_behavior is None:
                         self.assertEqual(coverage_issues, [])