Restore common|chrome/mainmenu-prompts.yaml

mainmenu-prompts.yaml was commented in d2 mod.
But it is used in latest versions of OpenRA and need to be
uncommented again.
This is also needed for PR #222 (Update mod to release-20230225)

mods/d2/mod.yaml

@@ -201,7 +201,7 @@ ChromeLayout:
 	common|chrome/ingame-debuginfo.yaml
 	common|chrome/ingame-infochat.yaml
 	d2k|chrome/mainmenu.yaml
-	#common|chrome/mainmenu-prompts.yaml
+	common|chrome/mainmenu-prompts.yaml
 	common|chrome/settings.yaml
 	common|chrome/credits.yaml
 	common|chrome/lobby.yaml