title: remove the first zeros of phone input TextFormField of type numbers flutter
body: <p>how can i remove the first zeros of phone number like 00963 and 031 and so on in flutter inside <code>TextFormField</code>   ?
  <br> here is my code of the<code>TextFormField</code> :
  <br></p>
  <pre><code>TextFormField(
               keyboardType: TextInputType.phone,
                onSaved: (input) =&gt; _con.user.phone = input,
               ),
  </code></pre>
  <p>my question is not to prevent the user enter the zeros but to get it with phone number without first zeros if the user entered it or not</p>