Blade @class directive renders class attribute even if its empty

[stoffpalette]

Blade's @Class directive should not render a class attribute, if every class-name is evaluated to false.

Currently, if you do @class(['first-class' => false, 'second-class' => false]) the rendered result is "class" instead of "".

[angeljqv]

It doesn't break anything

[stoffpalette]

No, it doesn't break if used standalone, but it is not expected and needless. Furthermore it is easy to fix.

[angeljqv]

it is easy to fix.

Feel free to make a PR