Deprecate ACCESSIBILITY_LARGE_POINTER_ICON setting

With the migration to vector cursors, this setting is no longer
used by the framework, and its value is not respected. Mark the
setting as deprecated.

Its functionality was removed by the following flag:
android.view.flags.enable_vector_cursor_a11y_settings

Bug: 438389806
Flag: EXEMPT deprecation of @hide api, docs only
Test: Presubmit
(cherry picked from https://android-review.googlesource.com/q/commit:7394ca744934792906c64b74a5c4e08661bb0cb9)
Merged-In: Ie15288e19a87987dfb195d764427f7b5892bb53b
Change-Id: Ie15288e19a87987dfb195d764427f7b5892bb53b