Partial flag clean up: Remove large mouse pointer in A11y Setting screen

Customization on mouse pointer has been moved to other screen, which is
released in 24Q4. Cleaning up the reference in a11y settings earlier for
cleaner ColorAndMotionScreen catalyst migration.

Bug: 346358375
Flag: EXEMPT partial clan up on android.view.flags.enable_vector_cursor_a11y_settings
Test: build succeed
Change-Id: Ie5c22f6cd1a55102240a86e13f17591e29ddbbf8