pytest: don't delete logs on-device (#32080)

fix log deletion

common/prefix.py

@@ -4,6 +4,7 @@ import uuid
 
 
 from openpilot.common.params import Params
+from openpilot.system.hardware import PC
 from openpilot.system.hardware.hw import Paths
 from openpilot.system.hardware.hw import DEFAULT_DOWNLOAD_CACHE_ROOT
 
@@ -45,6 +46,7 @@ class OpenpilotPrefix:
       shutil.rmtree(os.path.realpath(symlink_path), ignore_errors=True)
       os.remove(symlink_path)
     shutil.rmtree(self.msgq_path, ignore_errors=True)
+    if PC:
       shutil.rmtree(Paths.log_root(), ignore_errors=True)
     if not os.environ.get("COMMA_CACHE", False):
       shutil.rmtree(Paths.download_cache_root(), ignore_errors=True)