[Connected] Consolidate se23 logic and styles (#10068)

### WHY are these changes introduced?

Resolves #9929

### WHAT is this pull request doing?

Consolidates se23 beta styles for `Connected` (used for. connected text
fields)

### How to 🎩

Compare and make sure they are identical:

* This PR's [Storybook]()
* [Production
Storybook](https://storybook.polaris.shopify.com/?path=/story/all-components-textfield--with-connected-fields&globals=polarisSummerEditions2023:true)

polaris-react/src/components/Connected/Connected.scss

@@ -8,10 +8,7 @@
   // stylelint-enable
   position: relative;
   display: flex;
-
-  #{$se23} & {
-    align-items: center;
-  }
+  align-items: center;
 }
 
 .Item {