Add compatibility for php 8.4 by removing deprecation warnings

[PNardman]

Feature or problem being solved

Adding explicit nullable to parameters since implicit nullable parameters are deprecated in PHP 8.4

Affected code:

Status::L35
Satus::L47
ServerCallWrite::L94

Further details

Adding the explicit nullable parameter, gets rid of unnecessary deprecation warnings for php 8.4, however since we need to support php 7 we need to remove the type hinting, since php 7 does not support this feature.

Links / references

Implicitly nullable values are deprecated in php 8.4.

See:
https://php.watch/versions/8.4/implicitly-marking-parameter-type-nullable-deprecated

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[shu-yusa]

I think we should differentiate the (major) version to support 8.4 instead of removing the typing, and drop the support for php7?

[shu-yusa]

since php versions 7.x and 8.1 have reached EOL (https://www.php.net/supported-versions.php), how's dropping the support of 7.0 - 8.1, and publish the release as 2.0.0 for example? what do you think? cc: @stanley-cheung