Fix out of bounds config access in dataposter#3839

eljobe merged 2 commits intov3.8.x-releaseOffchainLabs/nitro:v3.8.x-releasefrom

v3.8.x-release-fix-empty-blob-tx-replacement-scheduleOffchainLabs/nitro:v3.8.x-release-fix-empty-blob-tx-replacement-scheduleCopy head branch name to clipboard