clearAllCachedAuthTokens method
Resets the state of the Identity API:
- Removes all OAuth2 access tokens from the token cache
 - Removes user's account preferences
 - De-authorizes the user from all auth flows
 
|callback| : Called when the state has been cleared.
Implementation
Future<void> clearAllCachedAuthTokens() async {
  await promiseToFuture<void>($js.chrome.identity.clearAllCachedAuthTokens());
}