Don't show name collisions for system contacts

ts/util/isInSystemContacts.ts

@@ -0,0 +1,12 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+export const isInSystemContacts = ({
+  type,
+  name,
+}: Readonly<{
+  type?: string;
+  name?: string;
+}>): boolean =>
+  // `direct` for redux, `private` for models and the database
+  (type === 'direct' || type === 'private') && typeof name === 'string';