Fix ackermann demo (backport #582)

[mergify]

From issue #438

1. According to the ros2_controllers documentation, the order of joints in ackermann_drive_controller.yaml is reversed.
2. The left front wheel and right front wheel are reversed in test_ackermann_drive.xacro.urdf.
3. The rotation direction of the front wheels is corrected.

I tested these changes on humble branch and the Ackermann vehicle worked well.

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This is an automatic backport of pull request #582 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 51c1d10 has failed:

On branch mergify/bp/kilted/pr-582
Your branch is up to date with 'origin/kilted'.

You are currently cherry-picking commit 51c1d10.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   gz_ros2_control_demos/urdf/test_ackermann_drive.xacro.urdf

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   gz_ros2_control_demos/config/ackermann_drive_controller.yaml

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally