Add simulation testing into CI/CD pipeline

[yuzhiliu8]

Add headless sim testing to further validate if new changes work

• check if vehicles arm
• check if simple missions complete
• check camera stream
• can incorporate scoring node logic potentially
• Multicopter, VTOL logic
• Payload logic as well

Currently, our ci-image workflow builds all necessary pre-built dependencies, so ROS, apt installs, pip installs, and any other binaries. It doesn't build anything from source. The main bottlenecks in rebuilding our workspace is compiling PX4-Autopilot, px4_msgs, and ros_gz, which we will all need for headless sim testing. Since the hashes/commits on these submodules don't change often, we can consider baking these into our ci-image.yml flow, so our ros-validate workflow pulls in an image with all necessary prebuilt dependencies and also PX4, px4_msgs, and ros_gz built from source.

We also need to install QGC and run it in headless mode via xvfb-run -a ./QGroundControl.AppImage to pass the ground station preflight check
also look into PX4_SIM_SPEED_FACTOR env var and see how high we can set this so that sim testing runs faster. We will need to do manual testing w/ this to see if it messes with consistency and how deterministic running sim is (we want to avoid random preflight fails or flight failures).