[terraform-ibm-observability-agents] Update example to show how to use logs agent filtering options

[ocofaigh]

It seems we have no examples in this repo which show how users can use the following features: logs_agent_additional_log_source_paths, logs_agent_exclude_log_source_paths, logs_agent_selected_log_source_paths

I suggest we update one of the example to show how they can be used (e.g perhaps show wildchar syntax), just like we did for exclude metrics here:

terraform-ibm-observability-agents/examples/obs-agent-ocp/main.tf

Lines 199 to 201 in b787459

	# example of how to include / exclude metrics - more info https://cloud.ibm.com/docs/monitoring?topic=monitoring-change_kube_agent#change_kube_agent_log_metrics
	cloud_monitoring_metrics_filter = [{ type = "exclude", name = "metricA.*" }, { type = "include", name = "metricB.*" }]
	cloud_monitoring_container_filter = [{ type = "exclude", parameter = "kubernetes.namespace.name", name = "kube-system" }]

Ensure to add code comments explaining the feature (just as we did above)