S3 HeadObject response should include ContentLength

[metadaddy]

Currently, the response from HeadObject does not include ContentLength. For example,

{
  AcceptRanges: 'bytes',
  LastModified: 2023-12-11T21:00:23.000Z,
  ETag: 'f0b0de38617496a96511a3353781515e',
  VersionId: '4_z834de8717f3677488b980413_f40189138ebbcef16_d20231211_m210023_c004_v0402012_t0025_u01702328423101',
  ContentType: 'application/octet-stream'
}

ContentLength is in the response from S3, but it is ignored by parseHeadersToResults. The HeadObject API Response Elements doc lists Content-Length, so it should be included.

[PR to closely follow]

[ryanblock]

Oh, I do so love how the content-length header is used contextually within the S3 API. 🫠

Thank you!