title: cant remove underline while entering text in TextField widget
body: <p>while entering text in text field there is an underline which persists till I am typing and goes when I close the keyboard I tried:</p>
  
  <pre><code> TextField(
                  style: TextStyle(
                    decoration: TextDecoration.none,
                    color: Colors.white,
                  ),
                  cursorColor: Colors.grey.withOpacity(0.8),
                  decoration: InputDecoration(
                    labelText: "email",
                    labelStyle: TextStyle(decoration: TextDecoration.none),
                    hintStyle: TextStyle(
                      color: Colors.grey,
                    ),
                    hintText: "email",
                    filled: true,
                    fillColor: Colors.grey.withOpacity(0.5),
                    prefixIcon: Icon(
                      Icons.alternate_email,
                      color: Colors.grey.withOpacity(0.8),
                    ),
                    enabledBorder: OutlineInputBorder(
                      borderRadius: BorderRadius.circular(100),
                      borderSide: BorderSide.none,
                    ),
                    focusedBorder: OutlineInputBorder(
                      borderRadius: BorderRadius.circular(100),
                      borderSide: BorderSide.none,
                    ),
                  ),
                ),
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/Ur3CM.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ur3CM.jpg" alt="enter image description here"></a></p>