Deprecate unused field types NAME_LAST_PREFIX and NAME_LAST_CORE

Deprecated and removed the field types NAME_LAST_PREFIX and
NAME_LAST_CORE from the client codebase. These field types are no longer
used and have no associated client-side logic. This change aligns with
the decision made during the feature sync.

OBSOLETE_HISTOGRAM=Removed as the considered field types are deprecated.

Bug: 507312647
Change-Id: Id640fdf1fc3971f5fe2ea29b5f759efab5f14b59
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7817334
Reviewed-by: Norge Vizcay <vizcay@google.com>
Reviewed-by: Maksim Moskvitin <mmoskvitin@google.com>
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Commit-Queue: Gianmarco Picarella <picarella@google.com>
Reviewed-by: Jihad Hanna <jihadghanna@google.com>
Cr-Commit-Position: refs/heads/main@{#1626776}