ci(workflows): shallow checkout and fail-fast in checks

Port checkout hygiene from the CI orchestrator branch
(mrpollo/ci_orchestration) to current workflows without merging the
orchestrator itself.

- checks.yml: enable fail-fast (99% success rate observed, cancel on
  first failure saves runner time), switch to fetch-depth 1, extract
  safe.directory to its own step
- itcm_check.yml: fetch-depth 1, drop submodules: recursive (the
  Makefile bootstraps submodules as a prerequisite of board targets)
- sitl_tests.yml, ros_integration_tests.yml, mavros_mission_tests.yml,
  mavros_offboard_tests.yml, python_checks.yml: fetch-depth 1

Each change matches the corresponding job in ci-orchestrator.yml on
mrpollo/ci_orchestration 1:1. Workflows that legitimately need history
(clang-tidy, flash_analysis, failsafe_sim, ros_translation_node,
ekf_*_change_indicator, build_all_targets) are left alone.

Signed-off-by: Ramon Roche <mrpollo@gmail.com>

.github/workflows/python_checks.yml

@@ -18,7 +18,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
       with:
-        fetch-depth: 0
+        fetch-depth: 1
 
     - name: Install Python3
       run: sudo apt-get install python3 python3-setuptools python3-pip -y