add auto scroll in dropdown user group filter

[NguyenThuyLan]

Prerequisites

• I have added steps to test this contribution in the description below

If there's an existing issue for this PR then this fixes

Description

This PR fixes for #19073

[nielslyngsoe]

Hi @NguyenThuyLan

Great that you looked into this.

Despite how great it would be that this modal can scroll, then this solution is not a great fit for v.13.
We do not know what extensions that already use this component, making a max height of 500 potentially a breaking change for their usage. This is the general problem with v.13.
We could be more clever, but as we don't know the specific cases I don't dare changing this. Mainly in the perspective that this is not actually a problem in v.13. (since the dropdown in v.13 expands the view so the user is already able to scroll)

I will close this PR, and then we will only fix this for v.16

Thanks