[Filebeat] system/auth module - Remove redundant grok wildcard

[TotalKnob]

What does this PR do?

The Grok pattern of filebeat had a redundant operator in the pattern, %{SPACE}+, resulting in the regex (?:\s*)+ which has the + as a redundant operator.

This issue is fixed by removing the redundant + operator.

Why is it important?

"Without this change, when the module's ingest pipelines are setup in Elasticsearch, the Elasticsearch server logs get flooded with warnings" #15900

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.

Related issues

#34249, #15840
Closes #34249

[mergify]

This pull request does not have a backport label.
If this is a bug or security fix, could you label this PR @TotalKnob? 🙏.
For such, you'll need to label your PR with:

• The upcoming major version of the Elastic Stack
• The upcoming minor version of the Elastic Stack (if you're not pushing a breaking change)

To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v8./d.0 is the label to automatically backport to the 8./d branch. /d is the digit

[elasticmachine]

💚 Build Succeeded

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Build stats

• Start Time: 2023-02-14T18:16:59.265+0000

• Duration: 68 min 22 sec

Test stats 🧪

Test	Results
Failed	0
Passed	7555
Skipped	746
Total	8301

💚 Flaky test report

Tests succeeded.

🤖 GitHub comments

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[elasticmachine]

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

[cmacknz]

/test

[cmacknz]

/test

[ShourieG]

LGTM

[andrewkroh]

The same change needs to be made to the system integration at

https://github.com/elastic/integrations/blob/5fca8c0314ab3ca2f184aea5eb2fa63e26954aee/packages/system/data_stream/auth/elasticsearch/ingest_pipeline/default.yml#L17