title: `leafletElement` is getting undefined in react-leaflet
body: <p>When I try the below code-sandbox link in my project. I'm facing issue like leafletElement is getting undefined.</p>
  <p>Below are the versions :-</p>
  <p>&quot;react-leaflet&quot;: &quot;^3.1.0&quot;,
  &quot;react-leaflet-enhanced-marker&quot;: &quot;^1.0.21&quot;,</p>
  <p><a href="https://codesandbox.io/s/relaxed-kepler-9sw2n?file=/src/App.js" rel="nofollow noreferrer">https://codesandbox.io/s/relaxed-kepler-9sw2n?file=/src/App.js</a></p>