Fix credentials "Autofill" function

[di72nn]

Fixes #986.

How it worked before:

1. Get API client list, find one named "Android app".
2. If not found, create a new API client. Response is ignored.
3. Get API client list, find one named "Android app". If a client with that particular name is not found, use any other.

The problem was that sometimes (not sure what it depends on) the list in the third step doesn't contain the newly created client. And if there is no other client (with a different name) to fall back to, the autofill fails.

To work around it I added a 1-second pause before the third step. I think this should do it.

There was also a 3+ years old TODO to use the creation result in step 2 (it contains credentials for the created client). I implemented this part, so it should be a little more optimized now.

So here's how it works now:

1. Get API client list, find one named "Android app".
2. If not found, create a new API client. Return the credentials if parsing succeeds (should work unless markup changes).
3. If the previous step failed, wait 1 second and proceed to step 4.
4. Get API client list, find one named "Android app". If a client with that particular name is not found, use any other.