[9.x] Removes unnecessary creatable API singleton parameter

[drradao]

Issue

Currently the creatable() and destroyable() methods in an API singleton resource route registartion accept boolean parameters that aren't taken into consideration later.

Route::apiSingleton('route', Controller::class)
    ->creatable()
    ->destroyable();

Possible solution

Removal of these parameters as suggested here

[GrahamCampbell]

This is strictly speaking a breaking change, so should go to master. In any case this is not a bug fix, so 9.x would not be appropriate.

[GrahamCampbell]

Oh, catching up on the other PR. I guess this is a bug fix. ;)

[drradao]

I guess it could be breaking if someone is passing a value there...

We could also add a comment in the parameter stating that the feature isn't there so people don't spam the optimize:clear command like maniacs thinking that they're cached 😄