internal/stub: move from container

This package solves a very specific stubbing use case, in a less than elegant manner.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/system/dispatcher_test.go

@@ -10,11 +10,11 @@ import (
 	"unsafe"
 
 	"hakurei.app/check"
-	"hakurei.app/container/stub"
 	"hakurei.app/hst"
 	"hakurei.app/internal/acl"
 	"hakurei.app/internal/dbus"
 	"hakurei.app/internal/pipewire"
+	"hakurei.app/internal/stub"
 	"hakurei.app/internal/xcb"
 )