fix(app): show the full user tag beside display names instead of a bare discriminator (#1696)

fluxer_app/src/features/channel/components/channel_header/useChannelHeaderData.ts

@@ -9,6 +9,7 @@ import {
 } from '@app/features/i18n/utils/CommonMessageDescriptors';
 import type {User} from '@app/features/user/models/User';
 import Users from '@app/features/user/state/Users';
+import * as NicknameUtils from '@app/features/user/utils/NicknameUtils';
 import {ChannelTypes} from '@fluxer/constants/src/ChannelConstants';
 import {useLingui} from '@lingui/react/macro';
 import {useMemo} from 'react';
@@ -39,12 +40,7 @@ export const useChannelHeaderData = (channel?: Channel): ChannelHeaderData => {
 		}
 		return Users.getUser(channel.recipientIds[0]) ?? null;
 	}, [channel, isDM]);
-	const directMessageName = useMemo(() => {
-		if (!isDM || !recipient) {
-			return '';
-		}
-		return recipient.displayName;
-	}, [isDM, recipient]);
+	const directMessageName = isDM && recipient && channel ? NicknameUtils.getNickname(recipient, null, channel.id) : '';
 	const groupDMName = useMemo(() => {
 		if (!isGroupDM || !channel) {
 			return '';