[CVC storage IOS] Add .SavingWithCvc suffix to LogSaveCreditCardPromptResultIOS

This Cl is to add SavingWithCvc suffix for save card with CVC case and
stop logging LogSaveCreditCardPromptResultIOS if it is CVC save only
case. After this change, CardSaveType::kCardSaveWithCvc will log in
"Autofill.SaveCreditCardPromptResult.IOS" with suffix ".SavingWithCvc",
CardSaveType::kCardSaveOnly will log in
"Autofill.SaveCreditCardPromptResult.IOS" without suffix
".SavingWithCvc", CardSaveType::kCvcSaveOnly will not log in
"Autofill.SaveCreditCardPromptResult.IOS".

Bug: 440106992, 431857697

Change-Id: I4fa0cb6b955644f02dcc5af40215c7bce374119e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6868835
Reviewed-by: Jan Keitel <jkeitel@google.com>
Commit-Queue: Yiwen Qian <yiwenqian@google.com>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1512886}