Doesn't work properly with Don't Keep Activities mode

**Issue by [Nublo](https://github.com/Nublo)**
_Friday Jun 21, 2019 at 12:48 GMT_
_Originally opened as https://github.com/googlesamples/android-credentials/issues/39_

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**Steps to reproduce**

- Set Don't keep activities flag
- Open app -> You will see email dialog
- Fold the app
- Unfold
- Tap on the dialog with any email

**Result**
In the form you will see(label with email field), that you are still signOut.

**Expected result**
You will be signedIn(correct email is shown).

**Addition**
If after this steps you will fold/unfold application one more time you will be signedIn.
As expected.

I investigated a little bit, and looks like we are not receiving onActivityResult after first fold/unfold, but receive after second, which is super strange.

Reproduce the fold/unfold sequence with Android's Don't keep activities setting, then inspect the activity-result handling mentioned in the report. Done means selecting an email after the first fold/unfold shows the signed-in state and correct email, without requiring a second cycle.

Written by the indexing model from the issue text.