[PLT-7219] Fix username as default for Teammate Name Display setting (#7023)

* fix username as default for Teammate Name Display setting

* update localizeMessage at UsersAndTeamsSettings

webapp/i18n/en.json

@@ -904,9 +904,9 @@
   "admin.team.restrictTitle": "Restrict account creation to specified email domains:",
   "admin.team.restrict_direct_message_any": "Any user on the Mattermost server",
   "admin.team.restrict_direct_message_team": "Any member of the team",
-  "admin.team.showFullname": "Show first and last name (default)",
+  "admin.team.showFullname": "Show first and last name",
   "admin.team.showNickname": "Show nickname if one exists, otherwise show first and last name",
-  "admin.team.showUsername": "Show username",
+  "admin.team.showUsername": "Show username (default)",
   "admin.team.siteNameDescription": "Name of service shown in login screens and UI.",
   "admin.team.siteNameExample": "E.g.: \"Mattermost\"",
   "admin.team.siteNameTitle": "Site Name:",
@@ -2241,10 +2241,6 @@
   "user.settings.display.nameOptsDesc": "Set how to display other user's names in posts and the Direct Messages list.",
   "user.settings.display.normalClock": "12-hour clock (example: 4:00 PM)",
   "user.settings.display.preferTime": "Select how you prefer time displayed.",
-  "user.settings.display.showFullname": "Show first and last name",
-  "user.settings.display.showNickname": "Show nickname if one exists, otherwise show first and last name",
-  "user.settings.display.showUsername": "Show username (default)",
-  "user.settings.display.teammateNameDisplay": "Teammate Name Display",
   "user.settings.display.theme.applyToAllTeams": "Apply new theme to all my teams",
   "user.settings.display.theme.customTheme": "Custom Theme",
   "user.settings.display.theme.describe": "Open to manage your theme",