OSV-2021-285 Use-of-uninitialized-value in grk::FileFormat::apply_palette_clr

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=30273 Crash type: Use-of-uninitialized-value Crash state: grk::FileFormat::applypaletteclr grk::FileFormat::decompress grkdecompress...