OSV-2024-830 UNKNOWN READ in ShadingImage::generateAxialBitmap

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=68375 Crash type: UNKNOWN READ Crash state: ShadingImage::generateAxialBitmap ShadingImage::generateBitmap SplashOutputDev::shadedFill...