New room list: move message preview in user settings (#30023)

* feat: move message preview settings to user settings

* test: update tests

* test(e2e): update preference screenshots

* test(e2e): update room list tests

* fix: display message preview settings only for new room list

* test(e2e): display all preference settings in screenshot

* test: update snapshot

src/settings/Settings.tsx

@@ -1136,6 +1136,7 @@ export const SETTINGS: Settings = {
     "RoomList.showMessagePreview": {
         supportedLevels: [SettingLevel.DEVICE],
         default: false,
+        displayName: _td("settings|show_message_previews"),
     },
     "RightPanel.phasesGlobal": {
         supportedLevels: [SettingLevel.DEVICE],