content: Misleading content on .ion-display-* classes

### URL

https://ionicframework.com/docs/layout/css-utilities#deprecated-classes

### Issue Description

The v8 documentation states that the `.ion-hide-*` classes are now deprecated and will be removed. It also mentions that the `.ion-display-*` classes are recommended to be used instead. It fails to mention that the `.ion-display-*` classes were only introduced in the latest minor version (8.7.0).

Open the linked layout CSS utilities documentation at the deprecated-classes section and review the wording around .ion-hide-* and .ion-display-* classes. Clarify that .ion-display-* was introduced in Ionic 8.7.0; the work is done when the version context is accurate and the recommendation is no longer misleading.

Written by the indexing model from the issue text.