[cisco_umbrella] Fix dns logs populating destination.ip instead of source.nat.ip

[adriansr]

What does this PR do?

Changes the Cisco Umbrella ingest pipeline to populate the source.nat.ip field instead of destination.ip.

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.

Related issues

• Relates Cisco Umbrella: Fix umbrella dns logs populating destination.ip instead of source.nat.ip beats#31454

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• Start Time: 2022-04-28T15:07:42.954+0000

• Duration: 16 min 27 sec

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Test	Results
Failed	0
Passed	7
Skipped	0
Total	7

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🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	100.0% (1/1)	💚
Files	100.0% (1/1)	💚 5.797
Classes	100.0% (1/1)	💚 5.797
Methods	93.75% (15/16)	👍 6.43
Lines	94.408% (287/304)	👍 4.684
Conditionals	100.0% (0/0)	💚