Deprecate AccessTokenAdapter.toAuthorizationCallback

[karolis-zukauskas]

AccessTokenAdapter.toAuthorizationCallback does not do what it is supposed to be doing - it should be deprecated to prevent further misuse.

This function returns a function that always returns the same accessToken (which is pointless). Instead, you want a function that might return a new accessToken if the old one expires.

The following code is correct for an authorization parameter:

const authorization = async () => {
  const token = await IModelApp.getAccessToken();

  return AccessTokenAdapter.toAuthorization(token);
}

This is wrong:

const accessToken = await IModelApp.getAccessToken();
const authorization = AccessTokenAdapter.toAuthorizationCallback(accessToken);