[7.x] [ftr] migrate "find" service to FtrService class (#100509)

[kibanamachine]

Backports the following commits to 7.x:

• [ftr] migrate "find" service to FtrService class ([ftr] migrate "find" service to FtrService class #100509)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 4eaf680
• Storybooks Preview

Metrics [docs]

Unknown metric groups

References to deprecated APIs

id	before	after	diff
canvas	29	25	-4
crossClusterReplication	8	6	-2
lens	67	45	-22
licensing	18	15	-3
lists	239	236	-3
monitoring	109	56	-53
securitySolution	386	342	-44
total			-131

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

cc @spalger