da: reuse useblobs for multiframetxs

[tuxcanfly]

Overview

This PR reuses the UseBlobs flag for multi frame transactions. OP doesn't make a distinction between multiple frames and blob da, however, we need to handle them separately to have multi frame txs, therefore some hacks around txdata.asBlob are required. op-batcher can continue to use the multi-frame-txs flag to enable multiframetxs on celestia.