packages/sophos/xg: fix kv split and handle syslog headers

[efd6]

What does this PR do?

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

• Check against changes in x-pack/filebeat/module/sophos/xg: fix kv field separation and add support for timestamped log line beats#29331

How to test this PR locally

Standard package testing.

Related issues

• Relates x-pack/filebeat/module/sophos/xg: fix kv field separation and add support for timestamped log line beats#29331

Screenshots

N/A

[elasticmachine]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Start Time: 2021-12-16T05:43:34.000+0000

• Duration: 23 min 43 sec

• Commit: 243bab4

Test stats 🧪

Test	Results
Failed	0
Passed	14
Skipped	0
Total	14

🤖 GitHub comments

To re-run your PR in the CI, just comment with:

• /test : Re-trigger the build.

[elasticmachine]

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

[efd6]

The failing cases need a quote-aware split processor to pass.

[efd6]

This failure is a fundamental inability for the KV processor to understand paired delimiters (quotes in this case) that make characters opaque.

[efd6]

Same here.