[PickerInput]: prop emptyValue doesn't work correctly with null value for selectionMode multi

[MSt1ch]

Prerequisites (optional)

This section may be deleted

Please answer the following questions for yourself before submitting an issue.

• [x] I am running the latest version
• [x] I checked the documentation and found no answer
• [x] I checked to make sure that this issue has not already been filed

Steps to Reproduce

1. Select some values
2. Then clear all
3. The empty value is still empty Array ([])

Actual result

What is the current behavior?

https://codesandbox.io/p/sandbox/uui-forked-j5tcv5?file=%2FExample.tsx%3A16%2C27

Expected result

I'm waiting null for empty select.

Environment

Please provide any relevant information about your setup. This is important in case the issue is not reproducible except for under certain conditions.

• UUI version: Latest (5.7.2)
• Browser name: all
• Operating System: all

[NatalliaAlieva]

Released in 5.8.0 ver.