journald: add missing source.ip and host.ip ECS fields

[mauri870]

Proposed commit message

This commit adds the missing ECS mappings for source.ip and host.ip. Since these fields were not mapped, they defaulted to keyword in logs from journald, causing conflicts in the data view.

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

How to test

Maybe there is a faster way, but what I did is the following:

• Deploy a 8.12.1 cloud stack
• Enroll an agent
• Install the journald integration in the agent policy
• In Discover, visualize the host.ip field, it shows as conflict (keyword, ip)
• Package the integration and deploy to the existing cluster: elastic-package install --zip ./integrations/build/packages/journald-1.1.1.zip -v
• Update the integration in the agent policy
• In the new index after the rollover, confirm that mappings are correct (host.ip and source.ip are shown as ip)
• Delete the old conflicting index
• Check new data in Kibana, source.ip and host.ip are shown as ip and no conflict is reported.

Related issues

• Fixes [journald] ECS conflicts with host.ip and source.ip fields #9690

Screenshots

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 3926b61

cc @mauri870

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)