Improve function setDisabled()

This commit removes deleting value of disabled form control. The reason why deleting value was implemented in this method is from is unclear and is now obsolete. Deleting value of the control makes use of the method complicated and tricky while the deleting itself has no real meaning.

src/Forms/Controls/BaseControl.php

@@ -179,16 +179,16 @@ public function setDefaultValue($value): static
 	/**
 	 * Disables or enables control.
 	 */
-	public function setDisabled(bool $value = true): static
-	{
-		if ($this->disabled = (bool) $value) {
-			$this->setValue(null);
-		} elseif (($form = $this->getForm(false)) && $form->isAnchored() && $form->isSubmitted()) {
-			$this->loadHttpData();
-		}
+	 public function setDisabled(bool $value = true)
+         {
+             $justEnabled = $this->disabled && $value === false;
+             $this->disabled = $value;
+             if($justEnabled && ($form = $this->getForm(false)) && $form->isAnchored() && $form->isSubmitted()){
+                 $this->loadHttpData();
+             }
+             return $this;
+         }
 
-		return $this;
-	}
 
 
 	/**