Nodes who are not currently master do not update the ElectMasterService when dynamically setting min_master_nodes

When updating the min_master_nodes setting via the Cluster Settings API, the change is propagated to all nodes. The current master node also updates the ElectMasterService and validates that is still sees enough master eligible nodes and that it's election is still valid. Other master eligible nodes do not go through this validation (good) but also didn't update the ElectMasterService with the new settings. The result is that if the current master goes away, the next election will not be done with the latest setting.

Note - min_master_node set in the elasticsearch.yml file are processed correctly

Closes #5494