Upgrade to oik-privacy-policy v1.4.6 for support for PHP 8.1 or PHP 8.2

Changes
| Change | Reference |
|---|---|
| Changed: Support PHP 8.1 and PHP 8.2 | bobbingwide/oik-privacy-policy#8 |
Tested
- Tested: With WordPress 6.3.1 and WordPress Multisite
- Tested: With WordPress 6.4-beta2 and WordPress Multisite
- Tested: With PHPUnit 9.6
- Tested: With PHP 8.0, PHP 8.1 and PHP 8.2
