[Fleet] clean up for deleted file task

[joeypoon]

Summary

Follow up PR to address comments from #144494 (review).

• rename index constants to _PATTERN
• use FileStatus from files-plugin

For maintainers

• This was checked for breaking API changes and was labeled appropriately

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[juliaElastic]

🚀

[juliaElastic]

@elasticmachine merge upstream

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 18aad9b

Metrics [docs]

Unknown metric groups

ESLint disabled in files

id	before	after	diff
osquery	1	2	+1

ESLint disabled line counts

id	before	after	diff
enterpriseSearch	19	21	+2
fleet	58	64	+6
osquery	108	113	+5
securitySolution	440	446	+6
total			+19

Total ESLint disabled count

id	before	after	diff
enterpriseSearch	20	22	+2
fleet	66	72	+6
osquery	109	115	+6
securitySolution	517	523	+6
total			+20

History

• 💚 Build #85505 succeeded 1de84f0

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[paul-tavares]

Thank you