Update the documentation to include enable_monitoring_dashboard

Author: tabito-hara

website/docs/r/networkfirewall_logging_configuration.html.markdown

@@ -70,6 +70,7 @@ This resource supports the following arguments:
 
 * `region` - (Optional) Region where this resource will be [managed](https://docs.aws.amazon.com/general/latest/gr/rande.html#regional-endpoints). Defaults to the Region set in the [provider configuration](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#aws-configuration-reference).
 * `firewall_arn` - (Required, Forces new resource) The Amazon Resource Name (ARN) of the Network Firewall firewall.
+* `enable_monitoring_dashboard` - (Optional) Whether to enable the detailed firewall monitoring dashboard on the firewall. Defaults to `false`.
 * `logging_configuration` - (Required) A configuration block describing how AWS Network Firewall performs logging for a firewall. See [Logging Configuration](#logging-configuration) below for details.
 
 ### Logging Configuration