Error parsing key value pair using key_value_parser operator

[ericwholt]

Describe the bug
   When using the key_value_parser the following example will fail.

{
"extensions":" fileid=3412341160002518171 sourceServiceName=site123.abcd.info siteid=1509732 suid=50005477 requestClientApplication=Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0 cs2=true cs2Label=Javascript Support cs3=true cs3Label=CO Support src=12.12.12.12 caIP=[13.13.13.13] ccode=[IL] tag=www.elvis.com cn1=200 in=54 xff=44.44.44.44 cs1=NOT_SUPPORTED cs1Label=Cap Support cs4=c2e72124-0e8a-4dd8-b13b-3da246af3ab2 cs4Label=VID cs5=de3c633ac428e0678f3aac20cf7f239431e54cbb8a17e8302f53653923305e1835a9cd871db32aa4fc7b8a9463366cc4 cs5Label=clappsigdproc cs6=Firefox cs6Label=clapp ccode=[IL] cicode=Rehovot cs7=31.8969 cs7Label=latitude cs8=34.8186 cs8Label=longitude Customer=CEFcustomer123 start=1453290121336 request=site123.abcd.info/ requestmethod=GET qstr=p\\=%2fetc%2fpasswd app=HTTP act=REQ_CHALLENGE_CAPTCHA deviceExternalID=33411452762204224 filetype=30037,1001, filepermission=2,1, cs9=Block Malicious User,High Risk Resources, cs9Label=Rule name"
}

To Reproduce
   Setup pipeline to parse extensions field using key_value_parser

Expected behavior
   That the key values will be parsed without error.

Environment:

• N/A
• 1.2.7

Error

{
   "level":"error",
   "timestamp":"2021-09-21T22:24:16.709-0400",
   "message":"Failed to process entry",
   "operator_id":"$.cef.extensions_parser",
   "operator_type":"key_value_parser",
   "error":"16 errors occurred:\n\t* expected '(Windows' to split by '=' into two items, got 1\n\t* expected 'NT' to split by '=' into two items, got 1\n\t* expected '6.1;' to split by '=' into two items, got 1\n\t* expected 'WOW64;' to split by '=' into two items, got 1\n\t* expected 'rv:40.0)' to split by '=' into two items, got 1\n\t* expected 'Gecko/20100101' to split by '=' into two items, got 1\n\t* expected 'Firefox/40.0' to split by '=' into two items, got 1\n\t* expected 'Support' to split by '=' into two items, got 1\n\t* expected 'Support' to split by '=' into two items, got 1\n\t* expected 'Support' to split by '=' into two items, got 1\n\t* expected 'qstr=p\\=%2fetc%2fpasswd' to split by '=' into two items, got 3\n\t* expected 'Malicious' to split by '=' into two items, got 1\n\t* expected 'User,High' to split by '=' into two items, got 1\n\t* expected 'Risk' to split by '=' into two items, got 1\n\t* expected 'Resources,' to split by '=' into two items, got 1\n\t* expected 'name' to split by '=' into two items, got 1\n\n",
   "action":"send",
   "entry":{
      "timestamp":"2021-09-21T22:24:16.709042-04:00",
      "severity":0,
      "labels":{
         "device":"SIEMintegration",
         "file_name":"cef_parser.log",
         "log_type":"cef",
         "plugin_id":"common_event_format",
         "version":"0"
      },
      "record":{
         "device_vendor":"Incapsula",
         "device_version":"1",
         "extensions":" fileid=3412341160002518171 sourceServiceName=site123.abcd.info siteid=1509732 suid=50005477 requestClientApplication=Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0 cs2=true cs2Label=Javascript Support cs3=true cs3Label=CO Support src=12.12.12.12 caIP=[13.13.13.13] ccode=[IL] tag=www.elvis.com cn1=200 in=54 xff=44.44.44.44 cs1=NOT_SUPPORTED cs1Label=Cap Support cs4=c2e72124-0e8a-4dd8-b13b-3da246af3ab2 cs4Label=VID cs5=de3c633ac428e0678f3aac20cf7f239431e54cbb8a17e8302f53653923305e1835a9cd871db32aa4fc7b8a9463366cc4 cs5Label=clappsigdproc cs6=Firefox cs6Label=clapp ccode=[IL] cicode=Rehovot cs7=31.8969 cs7Label=latitude cs8=34.8186 cs8Label=longitude Customer=CEFcustomer123 start=1453290121336 request=site123.abcd.info/ requestmethod=GET qstr=p\\=%2fetc%2fpasswd app=HTTP act=REQ_CHALLENGE_CAPTCHA deviceExternalID=33411452762204224 filetype=30037,1001, filepermission=2,1, cs9=Block Malicious User,High Risk Resources, cs9Label=Rule name",
         "message":"Illegal Resource Access",
         "severity":"9",
         "signature_id":"1"
      }
   }
}