title: KUSTO QUERY LANGUAGE (KQL) - Cannot unpack the dictionary
body: <p>I have a table wherein i uploaded the file with a column converted to json. but when im tryin to upack it using KQL. it does not work.</p>
  <pre><code>Id  Query Name  Workitem Id Logged Date Details
  0   Bug Stats   111 2022-06-08T02:26:43.111196Z {'AssignedTo': 'me', 'ClosedDate': None, 'CreatedDate': '2022-03-08T19:28:15.673Z', 'StartDate': None, 'State': 'For Review', 'Tags': 'tags', 'Title': 'Title', 'WorkItemType': 'Bug'}
  </code></pre>
  <p>Returns nothing</p>
  <pre><code>Datatable
  |extend  Details = parse_json(Details) //i tried todynamic() as well but same response
  |evaluate bag_unpack(Details) 
  </code></pre>
  
  <p>Returns Error:</p>
  
  <pre class="lang-html prettyprint-override"><code>Datatable
  |evaluate bag_unpack(Details) 
  </code></pre>
  <p>ERROR:
  Semantic error: evaluate bag_unpack(): the following error(s) occurred while evaluating the output schema: evaluate bag_unpack(): argument #1 expected to be a reference to a dynamic column. Query: 'DevopsQueriesTest |evaluate bag_unpack(Details) '</p>