vt: remove zero-width-space handling from conv_uni_to_pc()

This is now taken care of by ucs_is_zero_width().

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250417184849.475581-12-nico@fluxnic.net


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>