Many player functions behave inconsistently when passing an invalid player element

[patrikjuvonen]

Describe the bug
Many player functions process the element provided as CElement* instead of CPlayer*, causing inconsistency between some of the functions. For example, by providing root as the element, it will not throw a warning, while some of the functions do.

To Reproduce

1. getPlayerIP(root) -> false, no warning
2. getPlayerSerial(root) -> false, warning

Expected behavior
Make all functions work consistently. Specific class function -> require that specific class element.

MTA Client & Server
Multi Theft Auto v1.5.5-release-13977

Additional context

• Should probably also check out other classes while at it.
• I stumbled across to this problem while helping someone with a script problem on our Discord #scripting channel. They were using these two functions together and they asked me why does it throw an error on serial, but not on IP (IP was before serial). I then investigated and found these inconsistencies. And I agree, it is a stupid inconsistency that has to be fixed.
• Does not require backwards compatibility as the only thing changing is we're essentially adding a warning.

[Addlibs]

The reason why getPlayerIP (along with getPlayerName and getPlayerAccount) didn't give warnings when passed with a wrong type of element is because they work for multiple element types (that is, player as well as console). I've submitted a PR that adds warnings where necessary.

[patrikjuvonen]

Thanks for looking into the issue! Much appreciated. That's good info, I didn't quite even think of the console type at the time.