Fix attempt number for multi payload.

VerifyPayload() is called for every payload, so we shouldn't call
DownloadComplete() in there, move it to DownloadAction after all
payloads are applied.

Bug: 74980927
Test: check UpdateEngine.SuccessfulUpdate.AttemptCount in log
Test: update_engine_unittests
Change-Id: Iddb0ab111a7893f0c7bbf7a5119bd517ac5410a7
diff --git a/payload_consumer/download_action_unittest.cc b/payload_consumer/download_action_unittest.cc
index 7ec7e0e..daab924 100644
--- a/payload_consumer/download_action_unittest.cc
+++ b/payload_consumer/download_action_unittest.cc
@@ -177,6 +177,8 @@
       EXPECT_CALL(download_delegate,
                   BytesReceived(_, kMockHttpFetcherChunkSize, _));
     EXPECT_CALL(download_delegate, BytesReceived(_, _, _)).Times(AtLeast(1));
+    EXPECT_CALL(download_delegate, DownloadComplete())
+        .Times(fail_write == 0 ? 1 : 0);
   }
   ErrorCode expected_code = ErrorCode::kSuccess;
   if (fail_write > 0)