Use default interval for device access token polling in the generic OIDC broker #1163
Description
We reduced the device access token polling interval in ubuntu/authd-oidc-brokers#673 from 5 to 1 second to improve UX. That works fine with Entra ID and Google, but it turns out other IdPs don't like it: A hydra instance set up by the identity team keeps replying with "429 Too Many Requests" even though the golang.org/x/oauth2 package which we're using handles that error by increasing the interval by 5 seconds.
Let's follow the spec and use the default interval in the generic OIDC broker. The authd-msentraid and authd-google brokers should be able to override that, which requires adding a AccessTokenPollingInterval method to the provider interface - I'll create a separate issue for that.