Fuzz test with various blob sizes

[rootulp]

Context

#3072

Problem

We currently don't have a fuzz test that submits txs with blobs of various sizes. If the tx passes CheckTx then it should eventually get included in a block.

Proposal

We could use a fuzz test that submits blobs to the ante handler and verifies that if a valid PFB tx passes the ante handler then it also must be able to be included in an empty block (i.e. a block where it is the only tx).