Remove SlevomatCodingStandard.Functions.UnusedParameter

[asispts]

Coding standard can't be used for this purpose as it's unable to analyze code from a different file.

The main problem is that the rule can't ignore unused parameters that belong to the function definition inherited from parent methods or an interface. For example, in Symfony form, parameter $options is often unused, the rule will report it as unused. Although we can use phpcs:ignore to ignore this warning, it will add unnecessary technical debt.

public function buildForm(FormBuilderInterface $builder, array $options): void
{
    ...
}

We can use static analyzer for this task. See, for example, phpstan/phpstan#3031