title: Google one tap sign up always returns noCredentialsAvailable
body: <p>I have set up a bare bones test for the new google one tap sign in / sign up.</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html lang="en"&gt;
  
  &lt;head&gt;&lt;/head&gt;
  
  &lt;body&gt;
    &lt;script src="https://smartlock.google.com/client"&gt;&lt;/script&gt;
    &lt;script&gt;
      window.onGoogleYoloLoad = (googleyolo) =&gt; {
        googleyolo.hint({
          supportedAuthMethods: [
            "https://accounts.google.com"
          ],
          supportedIdTokenProviders: [{
            uri: "https://accounts.google.com",
            clientId: "xxxxx-xxxxx.googleusercontent.com"
          }],
          context: "signUp"
        }).then((credential) =&gt; {
          console.log(credential);
        }, (error) =&gt; {
          console.log(error.type);
        });
      };
    &lt;/script&gt;
  &lt;/body&gt;
  </code></pre>
  
  <p>I expected the above to either spit out the credential object to the console, or to prompt me to choose a google account to log in with. Instead a "noCredentialsAvailable" error type is thrown. This also happens when I use the <code>googleyolo.retrieve</code> promise.</p>
  
  <p>I currently:</p>
  
  <ul>
  <li>have a google account signed in and other "google sign in" oauth flows work</li>
  <li>am loading the above at localhost:3000 (which is also listed as an authorised origin on my google api credentials page)</li>
  </ul>
  
  <p>What am I missing?</p>