[Security][Gap Fill][9.3 & Serverless]: Doc auto gap fill feature

[nastasha-solomon]

Summary

Fixes #3969

This PR does the following:

• Renames the "Find rule execution gaps" section to "Find and resolve rule execution gaps".
• Chunks content for finding gaps, manually filling gaps, and automating the gap fill process.
  • The sections that underwent significant changes and need reviews are "Manually fill gaps" (cut out a lot of unnecessary content) and "Automatically fill gaps" (this is a new feature for 9.3).
• Refreshes the screenshot of the Rule Monitoring tab.

Generative AI disclosure

1. Did you use a generative AI (GenAI) tool to assist in creating this contribution?

• Yes
• No

[github-actions]

✅ Vale Linting Results

No issues found on modified lines!

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[github-actions]

🔍 Preview links for changed docs

• solutions/security/detect-and-alert/monitor-rule-executions.md

[approksiu]

@nastasha-solomon I think the license callout is missing in the doc for automated gap filling

[mdbirnstiehl]

A couple of suggestions, but otherwise LGTM!

[approksiu]

Changes specified in comments

[leemthompo]

rubber stamp on the .png file

[approksiu]

please modify interval

[approksiu]

LGTM! Thank you!

[nastasha-solomon]

Confirmed available on prod.