Use malloc for ESP32 data buffers to avoid issues

[embedded-creations]

https://community.pixelmatix.com/t/esp32-runs-out-of-some-ram-when-using-64x96/394/10

[marcmerlin]

I was going to open the bug but you beat me to it :) Suggested patch (which should mostly apply) if you remove the 2 files you don't have: https://github.com/marcmerlin/AnimatedGIFs/compare/29b155d7925301f89d88bf066ce28ddfffd7ee17...ec721ed993a7018b7ab481acb85a9e62880a9965