[UnmarshalJSON] check if line startsWith {

[LaurenceJJones]

adding this as a maybe task due to logging of errors.

Following crowdsecurity/crowdsec#2859 (comment) it might be a good idea to check if the line actually started with { if not then dont try to unmarshal json it as the user get bombarded with errors

[LaurenceJJones]

Also another task to add is adding type safety checks within all json parsers

time="2024-03-12T11:03:21Z" level=warning msg="failed to run RunTimeValue : cannot fetch 0 from <nil> (1:52)\n | evt.Unmarshaled.caddy.request.headers['User-Agent'][0]\n | ...................................................^" id=dry-frog name=crowdsecurity/caddy-logs stage=s01-parse
time="2024-03-12T11:03:21Z" level=warning msg="failed to run RunTimeValue : cannot fetch 0 from <nil> (1:52)\n | evt.Unmarshaled.caddy.request.headers['User-Agent'][0]\n | ...................................................^" id=dry-frog name=crowdsecurity/caddy-logs stage=s01-parse