chore(textarea): moving ios+md specific margin to native file

core/src/components/textarea/textarea.ionic.scss

 } 
 /** 
  * Ensures the textarea does not 
  * overlap the label. 
  */ 
 :host(.textarea-label-placement-stacked) textarea, 
 :host(.textarea-label-placement-floating) textarea, 
 :host(.textarea-label-placement-stacked[auto-grow]) .native-wrapper::after, 
 :host(.textarea-label-placement-floating[auto-grow]) .native-wrapper::after { 
   @include margin(8px, 0px, 0px, 0px); 
 } 
@@ -196,6 +196,18 @@
   transition: opacity globals.$ion-transition-time-150 globals.$ion-transition-curve-expressive;
 }
 
+// Textarea Label Placement - Stacked
+// ----------------------------------------------------------------
+
+/**
+ * Removes the margin between the textarea and the label,
+ * as ionic theme already handles the margin.
+ */
+:host(.textarea-label-placement-stacked) textarea,
+:host(.textarea-label-placement-stacked[auto-grow]) .native-wrapper::after {
+  @include globals.margin(0);
+}
+
 // Textarea Label Placement - Fixed
 // ----------------------------------------------------------------