Fix use-after-move in //c/b/ui/webui/chromeos/

Fix use-after-move (potential) bugs found by the
"bugprone-use-after-move" clang-tidy check.

Bug: 1122844
Change-Id: If11c9be19eb36a63b1281ae3eeb7543c3fa7c6a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2556678
Auto-Submit: Maksim Ivanov <emaxx@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832061}

chrome/browser/ui/webui/chromeos/onc_import_message_handler.cc

@@ -99,7 +99,8 @@ void OncImportMessageHandler::ImportONCToNSSDB(const std::string& callback_id,
     has_error = true;
     result += "Some certificates could not be parsed.\n";
   }
-  cert_importer->ImportAllCertificatesUserInitiated(
+  auto* const cert_importer_ptr = cert_importer.get();
+  cert_importer_ptr->ImportAllCertificatesUserInitiated(
       certs->server_or_authority_certificates(), certs->client_certificates(),
       base::BindOnce(&OncImportMessageHandler::OnCertificatesImported,
                      weak_factory_.GetWeakPtr(), std::move(cert_importer),