[Php81] Add NullToStrictIntPregSlitFuncCallLimitArgRector

[samsonasik]

Add rule to convert:

-        preg_split('/\s/', $output, NULL, PREG_SPLIT_NO_EMPTY);
+        preg_split('/\s/', $output, 0, PREG_SPLIT_NO_EMPTY);

The logic is shared with same converter and renamed to NullToStrictStringIntConverter that allow to convert for int purpose.

Fixes rectorphp/rector#9160

[samsonasik]

All checks have passed 🎉 @TomasVotruba it is ready for review.

[TomasVotruba]

Looks good 👍 thank you