use-cases/kubernetes/deployment.md guided onboarding section references wrong endpoint type

The guided onboarding section in [Deploy Elastic OpenTelemetry for Kubernetes observability](https://www.elastic.co/docs/solutions/observability/get-started/opentelemetry/use-cases/kubernetes/deployment) currently says:

> Make sure the shown in the installation command is valid for your environment. If not, replace it with the correct Elasticsearch endpoint.

The actual Kibana guided flow (**Add data → Kubernetes → Kubernetes monitoring with Elastic Agent**) now generates `elastic_otlp_endpoint` (a Managed OTLP endpoint), not `elastic_endpoint` (an Elasticsearch endpoint). The note and the surrounding text need to be updated to reflect that the endpoint is mOTLP, not Elasticsearch.

Open use-cases/kubernetes/deployment.md and read the guided onboarding section around the installation command. Update the note and surrounding text to identify elastic_otlp_endpoint as the Managed OTLP endpoint rather than an Elasticsearch endpoint; done means the section matches the current Kibana guided flow.

Written by the indexing model from the issue text.