[Cisco Umbrella] Add missing proxy config

[legoguy1000]

What does this PR do?

Add missing proxy config

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 [Cisco Umbrella] Proxy Support  #3803

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• Start Time: 2022-07-27T05:35:04.120+0000

• Duration: 15 min 46 sec

Test stats 🧪

Test	Results
Failed	0
Passed	8
Skipped	0
Total	8

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🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	100.0% (1/1)	💚
Files	100.0% (1/1)	💚 2.874
Classes	100.0% (1/1)	💚 2.874
Methods	94.444% (17/18)	👍 5.172
Lines	92.837% (324/349)	👍 2.251
Conditionals	100.0% (0/0)	💚