title: Firebase dynamic link handleUniversalLink returns nil dynamicLink after moving code to separate framework
body: <p>Dynamic links just recently stopped working in the dev branch of my iOS app and I cannot find the reason.
  handleUniversalLink callback systematically returns nil and when I do a DynamicLinks.performDiagnostics(...), I get the error message:</p>
  
  <blockquote>
    <p>ERROR: Specified custom URL scheme is (null) but Info.plist do not
    contain such scheme in CFBundleURLTypes key</p>
  </blockquote>
  
  <ol>
  <li><p>I  know that by the time I try to handle dynamic links, the Firebase stack is configured (I can query my Firebase database and retrieve data).</p></li>
  <li><p>I know the Firebase back end of my project works fine because the previous version of my app can still process dynamic links correctly.</p></li>
  <li><p>I did not make any changes to my info.plist of my GoogleService-Info.plist</p></li>
  </ol>
  
  <p>I obviously messed up something (maybe in the Firebase configuration code) but I cannot figure out what I did that caused Firebase dynamic links to stop working.
  Any idea on that ?</p>