ci: Remove generated folders from pyfluent directory to avoid a git error [skip tests] (#4692)

To avoid a later git error in self-hosted runner which is due to some
folder generated within the pyfluent directory while running the
external_compressible_flow.py example script:
1. Make sure FM_* folder is generated in a temp directory.
2. Delete the generated wing_workflow_files at the end of the script.

I think external_compressible_flow.py is the only problematic one based
on errors found in github logs (see the issue details).

---------

Co-authored-by: pyansys-ci-bot <92810346+pyansys-ci-bot@users.noreply.github.com>

Author: mkundu1

doc/changelog.d/4692.maintenance.md

@@ -0,0 +1 @@
+Remove generated folders from pyfluent directory to avoid a git error [skip tests]

examples/00-fluent/external_compressible_flow.py

@@ -67,6 +67,9 @@
 # the geometry files.
 
 # sphinx_gallery_thumbnail_path = '_static/external_compressible_flow.png'
+import shutil
+import tempfile
+
 import ansys.fluent.core as pyfluent
 from ansys.fluent.core import examples
 
@@ -88,6 +91,9 @@
 )
 print(meshing_session.get_fluent_version())
 
+tmpdir = tempfile.mkdtemp()
+meshing_session.preferences.MeshingWorkflow.TempFolder = tmpdir
+
 ###############################################################################
 # Initialize workflow
 # ~~~~~~~~~~~~~~~~~~~
@@ -374,4 +380,7 @@
 
 solver_session.exit()
 
+shutil.rmtree(tmpdir, ignore_errors=True)
+shutil.rmtree("wing_workflow_files", ignore_errors=True)
+
 ###############################################################################