[4.x]: "Not in" queries returning incorrect results for columns that have `null` values.

[nfourtythree]

What happened?

Description

When create queries that use syntax along the lines of ['not', 'a', 'b', 'c'] the Db helper method parseParam() refines this to the following SQL (based on the column name of myColumn)

WHERE (NOT (`table_name`.`myColumn` IN ('a', 'b', 'c')))

With the data below you would expect IDs 4, 5 and 6 returned but only 4 and 5 are.

ID	myColumn
1	'a'
2	'b'
3	'c'
4	'd'
5	''
6	null

Expected behavior

null values are returned when using "Not in"

Craft CMS version

4.x

PHP version

8.0

Operating system and version

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Database type and version

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