Docs: enable packages reference docs for 7-beta (#23953)

* added packages reference menu item.

* removed the draft flag.

* Updated docs by running script.

docs/sources/packages_api/ui/stylemixins.md

@@ -5,7 +5,6 @@
 title = "styleMixins"
 keywords = ["grafana","documentation","sdk","@grafana/ui"]
 type = "docs"
-draft = true
 +++
 
 ## styleMixins namespace
@@ -30,3 +29,9 @@ import { styleMixins } from '@grafana/ui';
 |  [listItem(theme)](./listitem/) |  |
 |  [listItemSelected(theme)](./listitemselected/) |  |
 
+## Variables
+
+|  Variable | Description |
+|  --- | --- |
+|  [focusCss](./focuscss/) |  |
+