[12.x] Fix nested can and inherit models on route groups

[bonroyage]

This fixes two issues with the can method on route groups. First, an exception if you defined can on multiple nested group levels. Second, that the models (second parameter) would not be inherited.

Exception with multiple nested group levels

  ErrorException 

  Array to string conversion

  at vendor/laravel/framework/src/Illuminate/Routing/Route.php:1103
    1099▕     {
    1100▕         $ability = enum_value($ability);
    1101▕ 
    1102▕         return empty($models)
  ➜ 1103▕             ? $this->middleware(['can:'.$ability])
    1104▕             : $this->middleware(['can:'.$ability.','.implode(',', Arr::wrap($models))]);
    1105▕     }
    1106▕ 
    1107▕     /**

Failing test result for testCanSetMiddlewareCanWithModelsOnGroups

Failed asserting that two strings are equal.
Expected :'can:view,post'
Actual   :'can:view'

Failing test result for testCanSetMiddlewareCanNestedOnGroups

Failed asserting that two arrays are equal.

Expected:
Array (
    0 => 'can:access-admin'
    1 => 'can:edit,post'
)

Actual:
Array (
    0 => 'can:Array'
)