refactor(range): remove legacy property and support for legacy syntax (#29040)

BREAKING CHANGE:

The `legacy` property and support for the legacy syntax, which involved placing an `ion-range` inside of an `ion-item` with an `ion-label`, have been removed from range. For more information on migrating from the legacy range syntax, refer to the [Range documentation](https://ionicframework.com/docs/api/range#migrating-from-legacy-range-syntax).

core/src/components/item/test/disabled/index.html

@@ -38,12 +38,6 @@
           <ion-item disabled href="#">
             <ion-label>Disabled Item Anchor</ion-label>
           </ion-item>
-
-          <ion-item>
-            <ion-range disabled value="10">
-              <span slot="label">Disabled Range</span>
-            </ion-range>
-          </ion-item>
         </ion-list>
       </ion-content>
 

core/src/components/item/test/legacy/disabled/index.html

@@ -38,11 +38,6 @@
           <ion-item disabled href="#">
             <ion-label>Disabled Item Anchor</ion-label>
           </ion-item>
-
-          <ion-item>
-            <ion-label>Disabled Range</ion-label>
-            <ion-range disabled value="10" legacy="true"></ion-range>
-          </ion-item>
         </ion-list>
       </ion-content>