UI scrollbars consistency

[DahmaniAdame]

Context

There are many occurrences of empty scroll bars with just the arrows but without anything to scroll.

It's caused by the use of:

.overflow-y-scroll {
    overflow-y: scroll;
}

Which forces a vertical scrollbar to be always be present, even if scrolling is not needed.

Using overflow-y: scroll; should help sort it out.

QA also reported that the design is sometimes different.

Expected behavior

No empty scrollbar should show up to avoid confusion.

All scrollbars should have the same design and colors.