[elastic_agent] Fix inconsistencies in field mapping types

[andrewkroh]

What does this PR do?

Fix mapping and description for the system.process.cpu.{system,user,total}.time.ms fields. The fields should be of type long instead of date.

Align mapping for the beat.stats.libbeat.config.{running,starts,stops} fields with the beat integration. The beat integration uses long so align to that.

For the message field, consistently use the ECS defined mapping type of match_only_text.

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.

Related issues

• Fixes [elastic_agent] field mappings trips up the ECS data quality checks #7846
• Fixes Elastic agent system.process.cpu mapping ms consistency  #4245

[elasticmachine]

Pinging @elastic/elastic-agent (Team:Elastic-Agent)

[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: 2023-09-19T14:47:41.159+0000

• Duration: 17 min 36 sec

Test stats 🧪

Test	Results
Failed	0
Passed	37
Skipped	0
Total	37

🤖 GitHub comments

Expand to view the GitHub comments

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

• /test : Re-trigger the build.

[elasticmachine]

🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	100.0% (0/0)	💚
Files	100.0% (0/0)	💚 3.689
Classes	100.0% (0/0)	💚 3.689
Methods	33.333% (25/75)	👎 -58.677
Lines	100.0% (0/0)	💚 12.022
Conditionals	100.0% (0/0)	💚

[cmacknz]

Thanks!

[elasticmachine]

Package elastic_agent - 1.13.1 containing this change is available at https://epr.elastic.co/search?package=elastic_agent

[elasticmachine]

Package elastic_agent - 1.13.1 containing this change is available at https://epr.elastic.co/search?package=elastic_agent

[elasticmachine]

Package elastic_agent - 1.13.1 containing this change is available at https://epr.elastic.co/search?package=elastic_agent