PixelPaint: Remove unused includes and method

Userland/Applications/PixelPaint/ProjectLoader.cpp

@@ -8,8 +8,6 @@
 #include "Image.h"
 #include "Layer.h"
 #include <AK/JsonObject.h>
-#include <AK/Result.h>
-#include <LibCore/MappedFile.h>
 #include <LibImageDecoderClient/Client.h>
 
 namespace PixelPaint {

Userland/Applications/PixelPaint/ProjectLoader.h

@@ -21,7 +21,6 @@ public:
     ErrorOr<void> load_from_file(NonnullOwnPtr<Core::File>);
 
     bool is_raw_image() const { return m_is_raw_image; }
-    bool has_image() const { return !m_image.is_null(); }
     RefPtr<Image> release_image() const { return move(m_image); }
     JsonArray const& json_metadata() const { return m_json_metadata; }