v1.6.8-rc.1

Full Changelog

• Upgrade to JS SDK 7.1.0-rc.1 and React SDK 2.9.0-rc.1
• Update from Weblate
  #14282
• Show a download completed toast in electron
  #14248
• Add the new spinner feature labs flag
  #14213
• Fix loading-test for SSO plaf changes
  #14212
• Fix spelling on startup error page
  #14199
• Document fonts in custom theme
  #14175
• Update from Weblate
  #14129
• ElectronPlatform: Implement the isRoomIndexed method.
  #13957
• ElectronPlatform: Add support to set and get the index user version.
  #14080
• Mark the new room list as ready for general testing
  #14102