Move the log popup to the main window

The quiz reports point changes with an event_logged signal, and the main
window adds them to the log. Alt+L is handled by the main window.

tests/integration/test_layout_unchanged.gd

@@ -13,7 +13,7 @@ const BASELINE_PATH: String = "res://tests/data/layout_baseline.json"
 ## Nodes that moved from the main window into the Quiz scene, by their old name.
 const QUIZ_NODES: Array[String] = [
 	"Open", "FileDialog", "MusicListPanel", "DebugLabel", "SettingsWindow",
-	"NewCharacterSelect", "WinnerWindow", "Log",
+	"NewCharacterSelect", "WinnerWindow",
 ]
 
 ## Nodes that moved into the Quiz scene under another path: old name to new path in