[BUG] zeek-files-labeler checks headers on Zeek JSON files when it should not

[verovaleros]

Describe the bug
The JSON conn.log files have no headers. Each line is a JSON line:

zeek@zeek:~/zeek-test/json$ cat conn.log
{"ts":1591367999.305988,"uid":"CMdzit1AMNsmfAIiQc","id.orig_h":"192.168.4.76","id.orig_p":36844,"id.resp_h":"192.168.4.1","id.resp_p":53,"proto":"udp","service":"dns","duration":0.06685185432434082,"orig_bytes":62,"resp_bytes":141,"conn_state":"SF","missed_bytes":0,"history":"Dd","orig_pkts":2,"orig_ip_bytes":118,"resp_pkts":2,"resp_ip_bytes":197}
{"ts":1591367999.430166,"uid":"C5bLoe2Mvxqhawzqqd","id.orig_h":"192.168.4.76","id.orig_p":46378,"id.resp_h":"31.3.245.133","id.resp_p":80,"proto":"tcp","service":"http","duration":0.25411510467529297,"orig_bytes":77,"resp_bytes":295,"conn_state":"SF","missed_bytes":0,"history":"ShADadFf","orig_pkts":6,"orig_ip_bytes":397,"resp_pkts":4,"resp_ip_bytes":511}

When running the zeek-files-labeler.py tool on a Zeek JSON file, the following error is shown:

Zeek Files labeler from labeled conn.log.labeled file. Version 0.1
https://stratosphereips.org
[+] Labeled file to use: dataset/test.log
The labeled file has not headers. Please add them.

To Reproduce
Sample Zeek JSON conn.log to test:

{"ts":1684227625.431351,"uid":"CMWzya3GuKbV6hku2l","id.orig_h":"192.168.1.243","id.orig_p":35358,"id.resp_h":"172.31.0.2","id.resp_p":12654,"proto":"tcp","service":"http","duration":6.867906093597412,"orig_bytes":531,"resp_bytes":0,"conn_state":"SH","local_orig":false,"local_resp":true,"missed_bytes":0,"history":"ScADFa","orig_pkts":6,"orig_ip_bytes":855,"resp_pkts":1,"resp_ip_bytes":52}
{"ts":1684227665.237912,"uid":"CRm5Me2cKCMEbBrDJc","id.orig_h":"192.168.1.18","id.orig_p":50118,"id.resp_h":"172.31.0.2","id.resp_p":12654,"proto":"tcp","service":"http","duration":5.09847617149353,"orig_bytes":625,"resp_bytes":0,"conn_state":"SH","local_orig":false,"local_resp":true,"missed_bytes":0,"history":"ScADFa","orig_pkts":8,"orig_ip_bytes":957,"resp_pkts":1,"resp_ip_bytes":40}
{"ts":1684227665.237911,"uid":"CXzhcA3CmZhXikjFQk","id.orig_h":"192.168.1.18","id.orig_p":50117,"id.resp_h":"172.31.0.2","id.resp_p":12654,"proto":"tcp","service":"http","duration":5.098514080047607,"orig_bytes":626,"resp_bytes":0,"conn_state":"SH","local_orig":false,"local_resp":true,"missed_bytes":0,"history":"ScADFa","orig_pkts":8,"orig_ip_bytes":958,"resp_pkts":1,"resp_ip_bytes":40}
{"ts":1684227664.630489,"uid":"ChtLqc1NJMnOu1maA7","id.orig_h":"192.168.1.18","id.orig_p":50110,"id.resp_h":"172.31.0.2","id.resp_p":12654,"proto":"tcp","service":"http","duration":5.712158918380737,"orig_bytes":1252,"resp_bytes":0,"conn_state":"SH","local_orig":false,"local_resp":true,"missed_bytes":0,"history":"ScADcFa","orig_pkts":45,"orig_ip_bytes":3064,"resp_pkts":1,"resp_ip_bytes":40}
{"ts":1684227665.23784,"uid":"C5l2rP1L5skfzoAZaa","id.orig_h":"192.168.1.18","id.orig_p":50119,"id.resp_h":"172.31.0.2","id.resp_p":12654,"proto":"tcp","service":"http","duration":5.12164306640625,"orig_bytes":946,"resp_bytes":0,"conn_state":"SH","local_orig":false,"local_resp":true,"missed_bytes":0,"history":"ScADcFa","orig_pkts":14,"orig_ip_bytes":1518,"resp_pkts":1,"resp_ip_bytes":40}
{"ts":1684227665.236117,"uid":"CYp05kkOOJ3pCe8Vb","id.orig_h":"192.168.1.18","id.orig_p":50116,"id.resp_h":"172.31.0.2","id.resp_p":12654,"proto":"tcp","service":"http","duration":5.1245081424713135,"orig_bytes":939,"resp_bytes":0,"conn_state":"SH","local_orig":false,"local_resp":true,"missed_bytes":0,"history":"ScADcFa","orig_pkts":11,"orig_ip_bytes":1391,"resp_pkts":1,"resp_ip_bytes":40}
{"ts":1684227664.630591,"uid":"CBghhD3zflPexGTckj","id.orig_h":"192.168.1.18","id.orig_p":50111,"id.resp_h":"172.31.0.2","id.resp_p":12654,"proto":"tcp","service":"http","duration":5.730525016784668,"orig_bytes":1253,"resp_bytes":0,"conn_state":"SH","local_orig":false,"local_resp":true,"missed_bytes":0,"history":"ScADcF","orig_pkts":21,"orig_ip_bytes":2105,"resp_pkts":0,"resp_ip_bytes":0}
{"ts":1684227665.255085,"uid":"CtWt0LXsI5Wv8gp71","id.orig_h":"192.168.1.18","id.orig_p":50121,"id.resp_h":"172.31.0.2","id.resp_p":12654,"proto":"tcp","service":"http","duration":5.215744972229004,"orig_bytes":674,"resp_bytes":0,"conn_state":"SH","local_orig":false,"local_resp":true,"missed_bytes":0,"history":"ScADFa","orig_pkts":9,"orig_ip_bytes":1046,"resp_pkts":1,"resp_ip_bytes":40}
{"ts":1684227665.25312,"uid":"CaCebC3q1DDGFKUNch","id.orig_h":"192.168.1.18","id.orig_p":50120,"id.resp_h":"172.31.0.2","id.resp_p":12654,"proto":"tcp","service":"http","duration":5.284203052520752,"orig_bytes":1017,"resp_bytes":0,"conn_state":"SH","local_orig":false,"local_resp":true,"missed_bytes":0,"history":"ScADcFa","orig_pkts":14,"orig_ip_bytes":1589,"resp_pkts":1,"resp_ip_bytes":40}
{"ts":1684227665.421915,"uid":"CYQlIQoh90Anqd2ae","id.orig_h":"192.168.1.18","id.orig_p":50123,"id.resp_h":"172.31.0.2","id.resp_p":12654,"proto":"tcp","duration":5.478057861328125,"orig_bytes":0,"resp_bytes":0,"conn_state":"SH","local_orig":false,"local_resp":true,"missed_bytes":0,"history":"ScAF","orig_pkts":4,"orig_ip_bytes":172,"resp_pkts":0,"resp_ip_bytes":0}

Expected behaviour
Expect the tool to parse this type of logs without error or print an unsupported type message.

Resources
Check documentation here: https://docs.zeek.org/en/master/log-formats.html