Merge the autofill provider's inline spec with the IME's spec for authentication case

* the autofill provider may not copy over the style spec provided
  by the IME, therefore framework should do the merge
* we did this for the regular dataset, but forgot to do it for
  the authentication in the FillResponse, this patch fixes it
* it was caught by our CTS test when I remove the fallback to
  the deprecated support lib rendering API

Test: atest android.autofillservice.cts.inline
Bug: 155105465

Change-Id: I963625973f916325d183a542b73d2c40f312ce9c