Fix Autofill dialog does not work

Apps have only one chance to get Autofill dialog support, it requires
attaching the autofillable view before the Activity has finished
laying out. This change moves the doing request to the view being
laid out, that is the same timing with what Autofill is doing about
the view is auto focused but under different conditions.

Bug: 226674898
Test: atest android.autofillservice.cts.dialog.LoginActivityTest
Change-Id: I9018b8db8673e3b917a303476666ae766fbe7891