Fix for SELinux handling logic (#529)

* Fix for SELinux handling logic

The old procedure was crashing with signal 9 SIGKILL, this should fix that problem

backend/localplatform.py

@@ -43,4 +43,10 @@ def get_log_level() -> int:
     ]
 
 def get_selinux() -> bool:
-    return os.getenv("DECKY_SELINUX", "0") == "1"
+    if ON_LINUX:
+        from subprocess import check_output
+        try:
+          if (check_output("getenforce").decode("ascii").strip("\n") == "Enforcing"): return True
+        except FileNotFoundError:
+          pass
+    return False