BUG #18148: Handle null in a date/time fields when passing empty arrays issue

The following bug has been logged on the website:

Bug reference:      18148
Logged by:          jaafar melhem
Email address:      jaafarmelhem2591@gmail.com
PostgreSQL version: 14.6
Operating system:   linux-gnu
Description:

- I have 4 fields in a table, two are date type and two are time type, and i
have arrays to insert from them to this table.
- I have a function to insert to this table: IN "p_fromdates"
_varchar=NULL::character varying[], IN "p_todates" _varchar=NULL::character
varying[], IN "p_fromtimes" _varchar=NULL::character varying[], IN
"p_totimes" _varchar=NULL::character varying[],
- and I am inserting them like this : 
unnest(p_fromdates::_varchar)::date, unnest(p_todates::_varchar)::date,
unnest(p_fromtimes::_varchar)::time, 
unnest(p_totimes::_varchar)::time, 
- However when passing null values (empty arrays), the record is not
inserted, 
- I have tried to handle it but I didn't find any way, always the record is
not inserted if the 4 arrays are empty.
Postgresql version : PostgreSQL 14.6 on x86_64-pc-linux-gnu, compiled by gcc
(GCC) 8.5.0 20210514 (Red Hat 8.5.0-15), 64-bit