[BUG] MatchError in the live view

[Dennis Beatty]

This error was received in Sentry:

MatchError: no match of right hand side value: []
  File "lib/level10_web/live/game_live.ex", line 32, in Level10Web.GameLive.mount/3
  File "lib/phoenix_live_view/utils.ex", line 391, in anonymous fn/6 in Phoenix.LiveView.Utils.maybe_call_live_view_mount!/5
  File "/app/deps/telemetry/src/telemetry.erl", line 321, in :telemetry.span/3
  File "lib/phoenix_live_view/static.ex", line 278, in Phoenix.LiveView.Static.call_mount_and_handle_params!/5
  File "lib/phoenix_live_view/static.ex", line 119, in Phoenix.LiveView.Static.render/3
...
(3 additional frame(s) were not displayed)