[7.x] [ftr] migrate "toasts" service to FtrService class (#100613)

[kibanamachine]

Backports the following commits to 7.x:

• [ftr] migrate "toasts" service to FtrService class ([ftr] migrate "toasts" service to FtrService class #100613)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 7c70447
• Storybooks Preview

Metrics [docs]

Unknown metric groups

References to deprecated APIs

id	before	after	diff
canvas	29	25	-4
crossClusterReplication	8	6	-2
fleet	22	20	-2
globalSearch	4	2	-2
indexManagement	12	7	-5
infra	261	149	-112
lens	67	45	-22
licensing	18	15	-3
lists	239	236	-3
maps	286	208	-78
ml	121	115	-6
monitoring	109	56	-53
securitySolution	386	342	-44
stackAlerts	101	95	-6
total			-342

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

cc @spalger