Remove a pragma once from a cpp file

src/audio_core/sink/sink_stream.cpp

@@ -1,8 +1,6 @@
 // SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-#pragma once
-
 #include <array>
 #include <atomic>
 #include <memory>