system/security: fix handling of events 4674, 4738 and 4742

[efd6]

What does this PR do?

This fixes cases where NewUacValue and UserAccountControl are set to the
blank value ("-") in 4738 and 4742, and cases in 4674 where there is
more than one access mask value.

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

• Equivalent changes will need to be made in the windows package.
• Original event obtained from partial processing of XML events posted in Error in System integration  #3898.

How to test this PR locally

Related issues

• Fixes Error in System integration  #3898

Screenshots

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

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• Start Time: 2022-08-02T04:37:23.121+0000

• Duration: 16 min 17 sec

Test stats 🧪

Test	Results
Failed	0
Passed	271
Skipped	0
Total	271

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🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	100.0% (3/3)	💚
Files	100.0% (4/4)	💚 2.959
Classes	100.0% (4/4)	💚 2.959
Methods	60.759% (48/79)	👎 -29.116
Lines	98.793% (2702/2735)	👍 7.341
Conditionals	100.0% (0/0)	💚

[leehinman]

LGTM