PixelPaint: Remove declarations for non-existent methods

Author: https://github.com/AtkinsSJ
Commit: 65d03e3b9d
Pull-request: https://github.com/SerenityOS/serenity/pull/17203
Reviewed-by: https://github.com/linusg ✅

Userland/Applications/PixelPaint/ImageProcessor.h

@@ -61,7 +61,6 @@ public:
 
 private:
     ImageProcessor();
-    void processor_main();
 
     // Only the memory in the queue is in shared memory, i.e. the smart pointers themselves.
     // The actual data will remain in normal memory, but for this application we're not using multiple processes so it's fine.