Keep vanilla PATH as on the supported Linux OSes

This path change was meant to test issue
#209, which is moot in
our case, because:

- all currently supported Linux distributions (Ubuntu 20.04, 22.04, 24.04;
  Rocky 8, 9; Debian 10, 11, 12) have `/usr/bin` before `/bin` in `PATH`
- the Arch Linux distribution that is mentioned in the above-cited issue
  is not currently supported.

Author: popescu-v

.github/workflows/unit-tests.yml

@@ -106,9 +106,6 @@ jobs:
           OMPI_MCA_rmaps_base_oversubscribe: true
           PRTE_MCA_rmaps_default_mapping_policy: :oversubscribe
         run: |
-          # Make sure '/bin' is before '/usr/bin' in PATH
-          PATH=$(echo "/bin:"$PATH | sed 's#:/bin##')
-
           # This is needed so that the Git tag is parsed and the khiops-python
           # version is retrieved
           git config --global --add safe.directory $(realpath .)
@@ -191,9 +188,6 @@ jobs:
           # Force > 2 CPU cores to launch mpiexec
           KHIOPS_PROC_NUMBER: 4
         run: |-
-          # Make sure '/bin' is before '/usr/bin' in PATH
-          PATH=$(echo "/bin:"$PATH | sed 's#:/bin##')
-
           # Make sure MPI support is not loaded through env modules
           # Note: As Docker container's shell is non-interactive, environment
           # modules are currently not initializing the shell anyway