[Request]: Update OpenTelemetry plugin guidelines for Jenkins in CI/CD observability doc

### Description

Deploying the [OpenTelemetry plugin](https://plugins.jenkins.io/opentelemetry) version 3.1138 for Jenkins, I noticed some of the screenshots in our [documentation](https://www.elastic.co/guide/en/observability/current/ci-cd-observability.html) seem a little dated.

Could we update the screenshots of the sections "Configure the OpenTelemetry plugin" and "Install Jenkins dashboards in Kibana"?

I'd also suggest we clarify the authentication requirement (step 3) with where to get the token or API key from an Elastic deployment.

There are current images of the Kibana dashboards for Jenkins [here](https://github.com/jenkinsci/opentelemetry-plugin/blob/main/docs/DASHBOARDS.md#elastic). Instead of a "CI/CD Overview" dashboard, it creates a "Jenkins Overview" and a "Jenkins Provisioning" dashboard.

And here is a screenshot of a sample configuration of the plugin under Manage Jenkins > System for reference.

### Resources

[CI-CD observability documentation](https://www.elastic.co/guide/en/observability/current/ci-cd-observability.html)

### Which documentation set does this change impact?

Integrations

### Feature differences

None

### What release is this request related to?

8.13

### Collaboration model

The documentation team

### Point of contact.

**Main contact:** @ethel-gondim

**Stakeholders:** @a03nikki @DanielBrown2023