In the service-export.md doc, clarify that serviceexport can be used in use cases other than multi-cluster

[zijun726911]

Highlight and emphasize more that serviceexport can be used in not only muti-cluster use cases, but exporting the target groups and using it in VPC Lattice setup outside Kubernetes

aws-application-networking-k8s/docs/api-types/service-export.md

Lines 8 to 10 in 5553213

	Internally, creating a ServiceExport creates a standalone VPC Lattice [target group](https://docs.aws.amazon.com/vpc-lattice/latest/ug/target-groups.html).
	Even without ServiceImports, creating ServiceExports can be useful in case you only need the target groups created;
	for example, using target groups in the VPC Lattice setup outside Kubernetes.

https://amzn-aws.slack.com/archives/C03PJRR791U/p1704923247871789?thread_ts=1704835010.670379&cid=C03PJRR791U

[zijun726911]

Done by #630