title: List type casting error in dart when getting Map values as a List
body: <p>I'm getting the error below even when I set the type of the variable as List</p>
  <p><a href="https://i.stack.imgur.com/rbnhT.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rbnhT.png" alt="enter image description here" /></a></p>
  <p>Error persists in a dynamic List</p>
  <p><a href="https://i.stack.imgur.com/5MYsM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5MYsM.png" alt="enter image description here" /></a></p>
  <p>Version info of flutter:</p>
  <p><a href="https://i.stack.imgur.com/AeU41.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/AeU41.png" alt="enter image description here" /></a></p>