[Internal]: Update APM infrastructure tab docs to reflect it is GA

### Description

What: updating the APM infrastructure tab docs to reflect it is GA
When: as soon as possible
Why: To inform users and because after https://github.com/elastic/kibana/pull/271090 is merged, we will have a more visible doc links in the page.

Note: The doc link is https://ela.st/docs-apm-infrastructure-tab

### Resources

Updated the UI in https://github.com/elastic/kibana/pull/271090

### Which deployment methods does this change impact?

Elastic On-Prem and Cloud (all)

### Feature differences

_No response_

### What Elastic Stack release is this request related to?

N/A

### Serverless release

_No response_

### Collaboration model

The documentation team will create the first draft

### Point of contact.

**Main contact:** @sbelastic

**Stakeholders:**
@roshan-elastic