Fix include paths for ROS2 headers

[kgreenek]

This is a minor fix. I noticed a couple of include paths for ROS2 headers are using .h instead of .hpp, so it was failing to compile for me.

[fixposition-support]

Hi @kgreenek can you tell us which version of ROS2 are you using. Because your change seems to not work on ROS2 Foxy at least. (Works on Humble though)

[kgreenek]

Oh interesting, good thing for CI! I am using Humble.

I see that the tf2_eigen.h header is deprecated as of Humble, but it is still present -- it triggers a deprecation warning when compiling.

For more context, I'm building with bazel using these rules: https://github.com/mvukov/rules_ros2

I found out the bazel target for tf2_eigen does not include the deprecated .h file, which is why it didn't work for me: (https://github.com/mvukov/rules_ros2/blob/main/repositories/geometry2.BUILD.bazel#L139).

I see two ways I can fix this:

1. Update rules_ros2 to also include the deprecated .h header.
2. Update fixposition_driver to check for the existence of the .hpp header.

The benefit of 2 is you won't cause folks to hit the deprecation warning when building.

I went ahead and updated my PR to do approach 2. But if you prefer I do 1 instead, I am happy to do that.

[fixposition-support]

@kgreenek Thanks a lot for the contribution!