phase0/epoch_processing updated_participation_record spec test has wrong bits len

[dapplion]

The PendingAttestations from this spec test

https://github.com/ethereum/consensus-specs/blob/824ff970f5e6f0b3ba472e942ce6ca38ced0ecf0/tests/core/pyspec/eth2spec/test/phase0/epoch_processing/test_process_participation_record_updates.py#L15

Have aggregation_bits with bit length = 0, when the committee length for it is 4. Should aggregation_bits be set to a zero'ed value of length 4?

PendingAttestation

  {
    aggregation_bits: '0x01',
    data: {
      slot: '0',
      index: '0',
      beacon_block_root: '0x0000000000000000000000000000000000000000000000000000000000000000',
      source: [Object],
      target: [Object]
    },
    inclusion_delay: '0',
    proposer_index: '200'
  }

Shuffling

[
    15, 30,  6, 33, 14, 38,  9, 60, 61,  8, 45, 37,
    21,  1, 42, 11, 53, 36, 58, 55, 51, 23, 34, 54,
     2, 29, 43, 50, 62, 56,  3, 26, 63, 46, 57, 27,
    35, 12, 17, 10, 13,  0, 20,  4, 28, 41, 31, 52,
    24, 40,  5,  7, 25, 39, 49, 47, 32, 22, 19, 44,
    59, 48, 16, 18
  ]