title: FormGroup.valueChanges fires on 'change' & 'blur' only when the field type is "number"
body: <p><strong>Problem:</strong></p>
  
  <p>Stackblitz: <a href="https://stackblitz.com/edit/angular-feu1az" rel="nofollow noreferrer">https://stackblitz.com/edit/angular-feu1az</a></p>
  
  <p>If I change the value of Text 1 or Text 2 the event is firing once. But when I change the value of the last field, which is of type number, then it is firing on change and blur and this causes some problems in my webapp. </p>
  
  <p><strong>Question:</strong></p>
  
  <p>Why is the "valueChange" event triggering on 'change' and 'blur' when the field type is "number"?</p>
  
  <p>How I can prevent this?</p>
  
  <p>(Same behavior on Chrome/Firefox/EDGE)</p>