The SnapshotOfRegionAssignmentFromMeta.initialize call in FavoredNodeLoadBalancer is just a dummy one

After we introduced FavoredNodesManager, we do not need to load this information every time when balancing, as all the updates to favored nodes will go to FavoredNodesManager and it can update its in memory state accordingly.

The current SnapshotOfRegionAssignmentFromMeta.initialize is just a dummy one in FavoredNodeLoadBalancer, as we never use it in the method.

It will introduce a full scan on hbase:meta so let's just remove it.