[mullet m3] Call PrepareToFetch when credit card suggestions are shown.

Credit card fetching preflight call needs to be made when we show
masked server credit cards. BAM::DidShowSuggestions checked that
the triggering field type is of credit card group and the
CreditCardAccessManager::PrepareToFetchCreditCards checked that
the user has server credit cards to suggest.

Mullet M3 introduces the flow where the user is able to trigger
credit card suggestions on any form. Now BAM looks at the actual
list of shown suggestions and calls CreditCardAccessManager if
credit card suggestions were shown.

Bug: 1493361
Change-Id: I6dee16129c16294cb7f91ad4bcefb332c219196d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5104869
Commit-Queue: Timofey Chudakov <tchudakov@google.com>
Reviewed-by: Jihad Hanna <jihadghanna@google.com>
Reviewed-by: Jan Keitel <jkeitel@google.com>
Reviewed-by: Bruno Braga <brunobraga@google.com>
Cr-Commit-Position: refs/heads/main@{#1235765}