1295 add array as type in DataModel properties

[SilinMykola]

Description (*)
This PR adds an array as a type in DataModel properties

Fixed Issues (if relevant)

1. Fixes Please add array as type in DataModel properties #1295

Questions or comments

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with integration/functional tests (if applicable)
• All automated tests passed successfully (all builds are green)

[VitaliyBoyko]

This cast is unnecessary for the array, see how it works for the type string

/**
* Getter for Foo.
*
* @return array|null
*/
public function getFoo(): ?array
{
return $this->getData(self::FOO) === null ? null
: (array)$this->getData(self::FOO);
}

also please update the Changelog.md with the changes

[SilinMykola]

@VitaliyBoyko I made changes. Please check.
Thank you!