Reduce replication cost of FReplicatedAgentMoveTargetData

[Leroy231]

This may become irrelevant due to https://github.com/HaywireInteractive/OnAllFronts-Public/issues/920. Consider if we should skip it.

Currently any time we create a new move target action we replicate FReplicatedAgentMoveTargetData which has a bunch of properties which are only specific to NavMesh move, e.g. CachedPreviousActionLocation. We should find a way to replicate the NavMesh move properties only when relevant. One way to do this would be:

• [ ] Split this struct into two and replicate only the necessary ones when needed.
• [ ] Split the NavMesh move related logic in TMassClientBubbleMoveTargetHandler into a new TMassClientBubbleNavMeshMoveHandler.
• [ ] when we're updating move target, mark items dirty only in TMassClientBubbleMoveTargetHandler
• [ ] when we're updating NavMesh move, mark items dirty in TMassClientBubbleNavMeshMoveHandler
• [ ] Verify relevant test cases in https://docs.google.com/spreadsheets/d/1S4XTEZQUM7HirgvrpcbNeP1eHZ8XSETfQeswdt9ml3A/edit#gid=0

[Leroy231]

Not relevant anymore due to https://github.com/HaywireInteractive/OnAllFronts-Public/issues/920