[Autofill PCC][Save]: Fix Save for PCC

If the provider doesn't set proper SaveInfo, update it so that data can be
saved. This achieves 2 purposes.
1. It unblocks testing of the Save flow, and allows to dogfood the feature.
2. It's needed in cases PCC types are selected.

Test: atest android.autofillservice.cts.saveui.SimpleSaveActivityTest
Bug: 276398138

Change-Id: I6d1960c8a4349e8fe278a97554ac766845695873