Fix parameter length check for CLuaBaseEntity::addStatusEffect()

[ghost]

I affirm:

• [x] that I agree to Topaz Next's Limited Contributor License Agreement, as written on this date
• [x] that I have read the Contributing Guide and the Code of Conduct
• [x] that I've tested my code since the last commit in the PR, and will test after any later commits

Temporary:

• [x] that I understand there are large refactoring efforts going on right now, that these efforts touch every single Lua script and binding, and that my pull request might get put on hold to ensure there are not any conflicts with the refactoring work

Fixes #2395

CLuaBaseEntity::addStatusEffect() was enforcing 4 parameters, but accepts two different lengths:

1. If CLuaStatusEffect is passed, allow one parameter
2. If numeric args passed, require a minimum of four

Move 4 parameter requirement to the else block, and leverage arg.is for single param

[zach2good]

Great catch! :)