[Security Solution][Lists][PIT] - Update `getListItemByValues` to use PIT

[yctercero]

In an effort to reduce the number of expensive queries in Kiana, core is tracking efforts to move to the use of PIT rather than search queries that pull for 10,000 items.

See Kibana core ticket here.

File
https://github.com/elastic/kibana/blob/master/x-pack/plugins/lists/server/services/items/get_list_item_by_values.ts#L38

[elasticmachine]

Pinging @elastic/security-solution (Team: SecuritySolution)

[elasticmachine]

Pinging @elastic/security-detections-response (Team:Detections and Resp)