fix: protect set_target with try/except + cleanup build artifacts

.gitignore

@@ -1,3 +1,3 @@
 __pycache__/
 *.egg-info/
-build/
+build/*.pyc

face_tracker/main.py

@@ -129,7 +129,10 @@ class FaceTracker(ReachyMiniApp):
                 degrees=True
             )
             antennas = np.deg2rad(np.array([antenna_angle, antenna_angle]))
-            reachy_mini.set_target(head=head, antennas=antennas)
+            try:
+                reachy_mini.set_target(head=head, antennas=antennas)
+            except Exception:
+                pass
 
             time.sleep(0.02)