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/focuscss.md

@@ -0,0 +1,24 @@
++++
+# -----------------------------------------------------------------------
+# Do not edit this file. It is automatically generated by API Documenter.
+# -----------------------------------------------------------------------
+title = "focusCss"
+keywords = ["grafana","documentation","sdk","@grafana/ui"]
+type = "docs"
++++
+
+## styleMixins.focusCss variable
+
+### styleMixins.focusCss variable
+
+<b>Signature</b>
+
+```typescript
+focusCss: (theme: GrafanaTheme) => string
+```
+<b>Import</b>
+
+```typescript
+import { styleMixins } from '@grafana/ui';
+const { focusCss } = styleMixins;
+```