fix(stepfunctions-tasks): cloudwatchlogs service generates wrong action in role policy (#27623)

This PR fixes the bug that a wrong action in role policy is generated when `cloudwatchlogs` service is specified.

A correct action is `logs:xxx`, but current behavior is to `cloudwatchlogs:xxx` by using the `service` property.

Closes #27573.

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Author: go-to-k