auditd,system: add missing event.original mappings

[efd6]

What does this PR do?

This add missing event.original mapping for auditd/log and system/{auth,security}.

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.

Author's Checklist

• [ ]

How to test this PR locally

Related issues

• Closes [auditd] Missing event.original mapping #4005
• Closes [system] Missing event.original mappings #4006

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• Start Time: 2022-08-17T02:04:43.499+0000

• Duration: 19 min 32 sec

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Test	Results
Failed	0
Passed	285
Skipped	0
Total	285

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🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	100.0% (4/4)	💚
Files	100.0% (5/5)	💚 2.836
Classes	100.0% (5/5)	💚 2.836
Methods	67.021% (63/94)	👎 -22.674
Lines	98.435% (4842/4919)	👍 7.514
Conditionals	100.0% (0/0)	💚

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Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

[andrewkroh]

@elastic/elastic-agent-data-plane, can you please review the changes to the system integration.

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)