Fix ci-coverage-build.yml job

[nbbrooks]

This job is failing, probably for a couple reasons.

1. Rolling has targeted 24.04 for some time now (similar to Run coverage CI on Ubuntu 24.04 ros2_robotiq_gripper#56)

2. It is also using github.sha to retrieve raw github content, which does not exist for pull_request triggers

2. It looks like raw github content retrieval with authentication via ?token=${{ secrets.GITHUB_TOKEN }} is no longer supported. Since this is a public repo and I would be surprised if we somehow hit the raw limit for unauthenticated retrieval in CI jobs, I'm just removing it entirely.

The rolling jobs should still fail until #23 is merged in but this shouldn't get stuck on retrieving the vcs file from raw.githubcontent anymore.

[nbbrooks]

The coverage job is now failing at the expected place (same as the other Rolling jobs)

/home/runner/work/picknik_controllers/picknik_controllers/ros_ws/src/nn8lre94e7/picknik_controllers/picknik_reset_fault_controller/src/picknik_reset_fault_controller.cpp:65:51: error: ‘class realtime_tools::RealtimePublisher<example_interfaces::msg::Bool_<std::allocator > >’ has no member named ‘trylock’
65 | if (realtime_publisher_ && realtime_publisher_->trylock())
|