[REQUEST] [Security]: Entity store GA in 8.18

[natasha-moore-elastic]

Description

In 8.18, entity store is moving from tech preview to GA. We should remove the tech preview label from entity store docs.

Resources

Dev issue: https://github.com/elastic/security-team/issues/10958

Which documentation set does this change impact?

Elastic Cloud Hosted only

Feature differences

N/A

What release is this request related to?

8.18

Collaboration model

The documentation team

Point of contact.

Stakeholders: @joedatlive @jaredburgettelastic

[natasha-moore-elastic]

Completed in #414 and #590 during migration cleanup of 9.x docs.
Need to remove in 8.18 branch for 8.18 docs.