LibGfx: Provide an implementation for ImageDecoderPlugin::icc_data()

Author: https://github.com/LucasChollet
Commit: e721c74598
Pull-request: https://github.com/SerenityOS/serenity/pull/21657

Userland/Libraries/LibGfx/ImageFormats/GIFLoader.h

@@ -28,7 +28,6 @@ public:
     virtual size_t frame_count() override;
     virtual size_t first_animated_frame_index() override;
     virtual ErrorOr<ImageFrameDescriptor> frame(size_t index, Optional<IntSize> ideal_size = {}) override;
-    virtual ErrorOr<Optional<ReadonlyBytes>> icc_data() override;
 
 private:
     GIFImageDecoderPlugin(FixedMemoryStream);