mimecast: set event.kind:alert for appropriate events

[efd6]

Proposed commit message

See title.

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.
• I have verified that any added dashboard complies with Kibana's Dashboard good practices

Author's Checklist

• [ ]

How to test this PR locally

Related issues

• Closes [Mimecast] Add event.kind: alert to parse alert data #12600

Screenshots

Demonstration of External Alerts for mimecast.*:

[elastic-vault-github-plugin-prod]

🚀 Benchmarks report

Package mimecast 👍(4) 💚(0) 💔(7)

Expand to view

Data stream	Previous EPS	New EPS	Diff (%)	Result
ttp_ip_logs	22727.27	10752.69	-11974.58 (-52.69%)	💔
ttp_url_logs	8196.72	6802.72	-1394 (-17.01%)	💔
archive_search_logs	12345.68	8333.33	-4012.35 (-32.5%)	💔
cloud_integrated_logs	8849.56	7042.25	-1807.31 (-20.42%)	💔
siem_logs	3257.33	2247.19	-1010.14 (-31.01%)	💔
threat_intel_malware_customer	7246.38	4219.41	-3026.97 (-41.77%)	💔
ttp_ap_logs	10416.67	6622.52	-3794.15 (-36.42%)	💔

To see the full report comment with /test benchmark fullreport

[elasticmachine]

Pinging @elastic/security-service-integrations (Team:Security-Service Integrations)

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
82.4% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: b5515d7

History

• 💚 Build #22485 succeeded 57edaf1

cc @efd6