Everywhere: Add sv suffix to strings relying on StringView(char const*)

Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).

No functional changes.

Userland/Services/AudioServer/Mixer.cpp

@@ -28,7 +28,7 @@ Mixer::Mixer(NonnullRefPtr<Core::ConfigFile> config)
               mix();
               return 0;
           },
-          "AudioServer[mixer]"))
+          "AudioServer[mixer]"sv))
     , m_config(move(config))
 {
     if (!m_device->open(Core::OpenMode::WriteOnly)) {