[3.1] Backport #3075 - Add check, if Offset is greater then stream length when reading bitmap colorMapSize#3091

JimBobSquarePants merged 2 commits intorelease/3.1.xSixLabors/ImageSharp:release/3.1.xfrom

af/backport-3075-to-3.1SixLabors/ImageSharp:af/backport-3075-to-3.1Copy head branch name to clipboard