Support Elastic Agent condition (and Kubernetes Leader Election)

[BenB196]

(I'm not 100% sure this is the correct repo, but I think its probably the best starting point to at least be moved to the correct spot).

Request

It would be nice if Synthetic monitors assigned to a Private location could leverage Elastic Agent conditions. (This would also support things like Leader Election)

Use Cases

1. As an operator of Kubernetes clusters, I'd like to have a synthetic monitor running on each cluster that reaches out to some endpoint to validate connectivity. To reduce management overhead, I'd like to have one Fleet Managed Elastic Agent per Kubernetes cluster node. To achieve this, I'd need to set a Synthetic private location on my Agent policy, and to not have this monitor run on all my nodes, I'd like to use the condition + leader election to only run the monitor on the currently elected leader.
2. As an operator of multiple Private locations that run in Kubernetes environments, I'd like to be able to define which environments specific monitors run via conditions, while still using the same private location for all monitors.

The lack of this functionality is currently limiting our want to adopt this part of the product.