AK: Move memory streams from LibCore

Author: https://github.com/timschumi
Commit: 093cf428a3
Pull-request: https://github.com/SerenityOS/serenity/pull/17173
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/alimpfard

Userland/Libraries/LibAudio/MP3Loader.cpp

@@ -31,7 +31,7 @@ Result<NonnullOwnPtr<MP3LoaderPlugin>, LoaderError> MP3LoaderPlugin::create(Stri
 
 Result<NonnullOwnPtr<MP3LoaderPlugin>, LoaderError> MP3LoaderPlugin::create(Bytes buffer)
 {
-    auto stream = LOADER_TRY(Core::Stream::FixedMemoryStream::construct(buffer));
+    auto stream = LOADER_TRY(FixedMemoryStream::construct(buffer));
     auto loader = make<MP3LoaderPlugin>(move(stream));
 
     LOADER_TRY(loader->initialize());