PixelPaint: Remove unused methods to access files directly

After transitioning to FileSystemAccessServer, some of the methods
in `MainWidget` and `ProjectLoader` for opening files directly with
a filename as opposed to with a file descriptor are unused. This
commit removes them.

Userland/Applications/PixelPaint/MainWidget.cpp

@@ -719,18 +719,6 @@ void MainWidget::open_image_fd(int fd, String const& path)
     m_layer_list_widget->set_image(&image);
 }
 
-void MainWidget::open_image_file(String const& path)
-{
-    auto try_load = m_loader.try_load_from_path(path);
-    if (try_load.is_error()) {
-        GUI::MessageBox::show_error(window(), String::formatted("Unable to open file: {}", path));
-        return;
-    }
-    auto& image = *m_loader.release_image();
-    create_new_editor(image);
-    m_layer_list_widget->set_image(&image);
-}
-
 void MainWidget::create_default_image()
 {
     auto image = Image::try_create_with_size({ 480, 360 });

Userland/Applications/PixelPaint/MainWidget.h

@@ -34,7 +34,6 @@ public:
     void initialize_menubar(GUI::Window&);
 
     void open_image_fd(int fd, String const& path);
-    void open_image_file(String const& path);
     void create_default_image();
 
 private:

Userland/Applications/PixelPaint/ProjectLoader.cpp

@@ -63,13 +63,5 @@ Result<void, String> ProjectLoader::try_load_from_fd_and_close(int fd, StringVie
     m_image = image;
     return {};
 }
-Result<void, String> ProjectLoader::try_load_from_path(StringView path)
-{
-    auto file_or_error = Core::File::open(path, Core::OpenMode::ReadOnly);
-    if (file_or_error.is_error())
-        return String::formatted("Unable to open file because: {}", file_or_error.release_error());
-
-    return try_load_from_fd_and_close(file_or_error.release_value()->leak_fd(), path);
-}
 
 }

Userland/Applications/PixelPaint/ProjectLoader.h

@@ -19,7 +19,6 @@ public:
     ~ProjectLoader() = default;
 
     Result<void, String> try_load_from_fd_and_close(int fd, StringView path);
-    Result<void, String> try_load_from_path(StringView path);
 
     bool is_raw_image() const { return m_is_raw_image; }
     bool has_image() const { return !m_image.is_null(); }