refactor(toggle): remove legacy property and support for legacy syntax (#29037)

BREAKING CHANGE:

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

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

@@ -39,10 +39,6 @@
             <ion-label>Disabled Item Anchor</ion-label>
           </ion-item>
 
-          <ion-item>
-            <ion-toggle disabled checked> Disabled Toggle </ion-toggle>
-          </ion-item>
-
           <ion-item>
             <ion-checkbox disabled checked> Disabled Checkbox </ion-checkbox>
           </ion-item>
@@ -85,7 +81,6 @@
 
           <ion-item>
             <ion-checkbox aria-label="Checkbox" slot="start"></ion-checkbox>
-            <ion-toggle disabled value="45">Checkbox + Toggle</ion-toggle>
           </ion-item>
 
           <ion-item>

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

@@ -38,12 +38,6 @@
           <ion-item disabled href="#">
             <ion-label>Disabled Item Anchor</ion-label>
           </ion-item>
-
-          <ion-item>
-            <ion-label>Disabled Toggle</ion-label>
-            <ion-toggle disabled checked slot="end" legacy="true"></ion-toggle>
-          </ion-item>
-
           <ion-item>
             <ion-label>Disabled Checkbox</ion-label>
             <ion-checkbox disabled checked slot="start" legacy="true"></ion-checkbox>
@@ -85,12 +79,6 @@
             <ion-range disabled value="45"></ion-range>
           </ion-item>
 
-          <ion-item>
-            <ion-checkbox slot="start" legacy="true"></ion-checkbox>
-            <ion-label>Checkbox + Toggle</ion-label>
-            <ion-toggle disabled value="45"></ion-toggle>
-          </ion-item>
-
           <ion-item>
             <ion-checkbox disabled slot="start" legacy="true"></ion-checkbox>
             <ion-label>Checkbox + Buttons</ion-label>