fix(material/slider): make valueChange emit only on change and not on…

… input (#26535)

(cherry picked from commit 6d89b9d)

src/material/slider/slider-input.ts

@@ -319,6 +319,7 @@ export class MatSliderThumb implements _MatSliderThumb, OnDestroy, ControlValueA
   }
 
   _onChange(): void {
+    this.valueChange.emit(this.value);
     // only used to handle the edge case where user
     // mousedown on the slider then uses arrow keys.
     if (this._isActive) {
@@ -327,7 +328,6 @@ export class MatSliderThumb implements _MatSliderThumb, OnDestroy, ControlValueA
   }
 
   _onInput(): void {
-    this.valueChange.emit(this.value);
     this._onChangeFn(this.value);
     // handles arrowing and updating the value when
     // a step is defined.