Describe the issue
On empty strings, the behaviour of the function CAST('', 'IPv6') changed between the versions 21.x and 22.x

How to reproduce
On 21.8.14.5:

SELECT CAST('', 'IPv6');
Returns: 
	
::

On 22.2.2.1:

SELECT CAST('', 'IPv6');
Triggers error: 

Code: 441. DB::Exception: Invalid IPv6 value.: While processing CAST('', 'IPv6'). (CANNOT_PARSE_DOMAIN_VALUE_FROM_STRING) (version 22.2.2.1)

Additional context
This can prevent some users from upgrading to 22.x when the use of this function is spread across a number of table definitions and environments. The following workaround CAST(toFixedString('', 16), 'IPv6') works but the manual task of updating all the occurrences is challenging.