Import Projects: Repeated hotkeys

- [x] I verified I can reproduce this issue against Eclipse 2026-03 (4.39.0)

## Steps to reproduce

From a fresh installation and clean workspace:
* _Open File_ -> _Import_
* Select _Existing Projects into Workspace_
* ❎ Repeated Alt + ... Hotkeys can be observed on the page.
* This means that _Add project to working sets_ and the _Select..._ button cannot be accessed. (I couldn't verify the last issue because of a system shortcut on Alt+R.)
(Please note that the two Browse buttons are not a problem because only one of them is active at any given time.)

I expected: That I can access all the hotkeys with the respective Alt + combination.

But got: Only the first option with the given Alt + combination can be accessed.

## Here is some relevant log output

From `/.metadata/.log`
No log entry relevant.

## Tested under this environment:
* OS & version: Windows 11 Enterprise 10.0.26100
* Eclipse IDE/Platform version (as shown in *Help > About*): Eclipse IDE for RCP and RAP Developers (includes Incubating components)
Version: 2026-03 (4.39.0)
Build id: 20260305-0817

## Community

- [x] I understand reporting an issue to this OSS project does not mandate anyone to fix it. Other contributors may consider the issue, or not, at their own convenience. The most efficient way to get it fixed is that I fix it myself and contribute it back as a good quality patch to the project.