Cherry-pick #19316 to 7.x: [Filebeat][Fortinet Module] Small bugfixes for time formats and IP address arrays

[leehinman]

Cherry-pick of PR #19316 to 7.x branch. Original message:

What does this PR do?

This PR resolves reported issues around the eventtime field being in both seconds and milliseconds and that the field ipaddr can also be an array.

Why is it important?

Resolves niche usecases that would otherwise throw an error

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Author's Checklist

Added new logs and reran nosetests to ensure it was fixed.

Related issues

• Closes [FileBeat] Fortinet module doesn't handle multiple IP addresses in dns.resolved_ip (ipaddr) field. #19154
• Closes Timezone parsing error in pipeline of Fortinet module #19010

[elasticmachine]

Pinging @elastic/siem (Team:SIEM)

[elasticmachine]

💚 Build Succeeded

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Build stats

• Build Cause: [Pull request #19373 updated]

• Start Time: 2020-06-25T14:16:38.628+0000

• Duration: 48 min 57 sec

Test stats 🧪

Test	Results
Failed	0
Passed	2344
Skipped	382
Total	2726

Steps errors

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• Name: Report to Codecov

  • Description: curl -sSLo codecov https://codecov.io/bash for i in auditbeat filebeat heartbeat libbeat metricbeat packetbeat winlogbeat journalbeat do FILE="${i}/build/coverage/full.cov" if [ -f "${FILE}" ]; then bash codecov -f "${FILE}" fi done

  • Duration: 1 min 27 sec

  • Start Time: 2020-06-25T14:59:34.705+0000

  • log