Upgrade to sb-chart-block v1.2.5 for PHP 8.1 and PHP 8.1 support

Changes
| Change | Reference |
|---|---|
| Changed: PHP 8.2 Declare class properties | bobbingwide/sb-chart-block#36 |
Tested
- Tested: With WordPress 6.4-RC1 and WordPress Multisite
- Tested: With PHP 8.1 and PHP 8.2
- Tested: With PHPUnit 9.6
