[AIAE] Append BNPL chip under credit card suggestions

Append BNPL chip to the credit card suggestions if a non-cvc field of
the credit card form is clicked, nothing filled in the card number
field, at least one BNPL issuer presents and the domain in eligible for
BNPL. This feature is guarded by flag
kAutofillEnableAiBasedAmountExtraction.

Low-Coverage-Reason: COVERAGE_UNDERREPORTED
Bug: 444684349
Change-Id: Ic7bea10533e56deed531645e4249c33e0fdae9fa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6977152
Reviewed-by: Vinny Persky <vinnypersky@google.com>
Reviewed-by: Norge Vizcay <vizcay@google.com>
Commit-Queue: James Sun <jamessun@google.com>
Cr-Commit-Position: refs/heads/main@{#1526873}