[FIX] Scrollbar not using new style

[ggazzo]

applied on sidenav and room

@RocketChat/core

Closes #8049

[karlprieb]

@ggazzo Could you use NPM module instead Meteor packages?

[ggazzo]

yes I can , but I won't <3

[ggazzo]

@MartinSchoeler could you see the error plz? :)

[ggazzo]

thanks @rodrigok

[cyclops24]

@ggazzo , @karlprieb , @rodrigok Please visit above issue. ( #8223 )

[rodrigok]

@cyclops24 It was my fault, the PR was in progress and with test erros, so I fixed the tests and thought was the reason to be in progress, so I merged it.

I created a new PR (#8244) disabling the scrollbar implementation and @ggazzo will finish the implementation in another PR.

Thanks by your review 😄