title: 'Android property not found.' error while building Flutter aar
body: <p>How to fix <code>Android property not found</code> error while <code>flutter build aar</code>?</p>
  
  <pre><code>FAILURE: Build failed with an exception.
  * Where:
  Initialization script '/Users/username/sdk/flutter/packages/flutter_tools/gradle/aar_init_script.gradle' line: 15
  * What went wrong:
  Android property not found.
  </code></pre>