[BTMan] Refactor NavigateTo to integrate with PPMan's signals and slots

Feature Request

Summary

Currently, NavigateTo is using a direct reference to a PathPlanner inside a util to get paths, but we want to use the infra around signals/slots to get paths from the PathPlanningManager instead.

Testing will be handled in #612 (closed)

Acceptance Criteria

• NavigateTo uses signals/slots for pathing, not direct reference to PathPlanner

Design / Technical Approach

Dependencies

Need to finish #461 (closed) first

Testing Plan

• Just make sure the tree is still constructable in a test
• Actual signal/slot implementation will be tested in #612 (closed)