title: Expression of type 'String' does not match the field 'expression' on If Condition in ADFv2
body: <p>I'm adding an If Condition to my ADFv2 Pipeline based on the output of an activity.  I'm simply checking if a file is downloaded and if so I want to load the table with the downloaded file.</p>
  
  <p>My Expression looks like this:</p>
  
  <pre><code>@{equals(activity('RunFunction').output.files[1].Downloaded,true)}
  </code></pre>
  
  <p>And I'm getting the following warning:</p>
  
  <pre><code>Expression of type 'String' does not match the field 'expression' 
  </code></pre>
  
  <p>How do I update my code to remove this warning?</p>