remove extraneous length checks in KZG batch proofs

[tersec]

These are replicated in https://github.com/ethereum/c-kzg-4844/blob/d637761a2ece4f13dbcffcae09253408e430a6e1/bindings/nim/kzg.nim#L181-L202

proc verifyProofs*(ctx: KzgCtx,
                  blobs: openArray[KzgBlob],
                  commitments: openArray[KzgBytes48],
                  proofs: openArray[KzgBytes48]): Result[bool, string] {.gcsafe.} =
  if blobs.len != commitments.len:
    return err($KZG_BADARGS)

  if blobs.len != proofs.len:
    return err($KZG_BADARGS)

  if blobs.len == 0:
    return ok(true)

...

Which is recognized by ethereum/consensus-specs@468b5be and ethereum/consensus-specs#3368

As such, the spec removed the wrapper function. It's useful to keep the wrapper here, because it coalesces the two failure modes of failure-in-trying-to-verify with successful verification, procedurally, which rejected the proof/commitment/blob tuple. Downstream code largely doesn't care, except insofar as it would like to be able to generate more informative error messages, so keeping this wrapper avoids code duplication elsewhere.

Still, it's not in spec as of v1.4.0, so remove consensus spec reference URL.

[github-actions]

Unit Test Results

         9 files  ±0    1 101 suites  ±0   27m 33s ⏱️ +7s
  4 213 tests ±0    3 866 ✔️ ±0  347 💤 ±0  0 ❌ ±0 
16 834 runs  ±0  16 436 ✔️ ±0  398 💤 ±0  0 ❌ ±0 

Results for commit ef5ef3d. ± Comparison against base commit 52ed0d6.