Does need the env-var on Linux.

But we need it opn platforms we might release an Enterprise edition for. Fortunately, Linux is not one of those platforms, so it all works out anyway.

CURA-8475

cura_app.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 
-# Copyright (c) 2020 Ultimaker B.V.
+# Copyright (c) 2022 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
 
 # Remove the working directory from sys.path.
@@ -15,7 +15,8 @@ if "" in sys.path:
 import argparse
 import faulthandler
 import os
-os.environ["QT_PLUGIN_PATH"] = ""  # Security workaround: Don't need it, and introduces an attack vector, so set to nul.
+if sys.platform != "linux":  # Turns out the Linux build _does_ use this, but we're not making an Enterprise release for that system anyway.
+    os.environ["QT_PLUGIN_PATH"] = ""  # Security workaround: Don't need it, and introduces an attack vector, so set to nul.
 
 from PyQt5.QtNetwork import QSslConfiguration, QSslSocket