fix(LibCarla/cmake): install ros2/dds/ headers in server cmake for Windows builds

[JArmandoAnaya]

Description

PR #9644 added #include "carla/ros2/dds/DDSMiddleware.h" to ROS2.h for the new Enable(bool, DDSMiddleware) signature, but did not update the server cmake header install list. This breaks the Windows CI build with:

carla/ros2/ROS2.h(13): fatal error C1083: cannot open include file:
    'carla/ros2/dds/DDSMiddleware.h': No such file or directory

Why this only affects Windows: LibCarla headers are installed to CarlaDependencies/include/ via two different cmake paths:

• Linux (make LibCarla ARGS="--ros2"): uses the ros2 build type, which delegates header installation to cmake/fast_dds/CMakeLists.txt. That file already installs all ros2/ subdirectories, including ros2/dds/. Working correctly.
• Windows (make LibCarla, no --ros2): uses the Server build type, which runs cmake/server/CMakeLists.txt. This file contains a manually maintained foreach loop that lists every subdirectory whose headers should be installed. It listed "ros2/" but not "ros2/dds/".

The UE4 plugin includes ROS2.h unconditionally (not behind #ifdef WITH_ROS2) from CarlaEngine.h, CarlaEpisode.h, ActorROS2Handler.h, and several sensor .cpp files. Before #9644, ROS2.h had no subdirectory dependencies, so the missing entry was not a problem.

Fix: add "ros2/dds/" to the server cmake foreach install loop, following the same pattern already used for other nested subdirectories ("opendrive/parser/", "road/element/", "streaming/detail/tcp/", etc.).

Why this must merge before #9645: PR #9645 (delete legacy FastDDS-generated types) cannot pass Windows CI until this header installation gap is fixed. The error is caused by code already merged in #9644, not by #9645 itself.

Where has this been tested?

• Platform(s): Ubuntu 22.04
• Python version(s): 3.10-3.12
• Unreal Engine version(s): 4.26

Tests:

make LibCarla ARGS="--ros2"    # builds server, client, ros2 targets
make check.LibCarla            # 114/114 server + 56/56 client tests pass

Header installation verified:

CarlaDependencies/include/carla/ros2/dds/DDSMiddleware.h  (present after build)

Possible Drawbacks

None. This is a pure addition to the CMake install list. It cannot affect existing installs, only adds previously missing headers. The Linux build path is unaffected because it uses a separate CMake target (cmake/fast_dds/CMakeLists.txt) that already installs these headers.

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This change is 

[update-docs]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would update our CHANGELOG.md based on your changes.

[JArmandoAnaya]

@LuisPovedaCano Hello, I'm creating this PR because I noticed that since PR #9644, there has been an issue building the Windows version of Carla. The issue looks like a minor problem, and a small change can resolve it. It is probably better to check whether this code change fixes the Windows build in GitHub CI before merging the PR #9645 to verify everything is correct.