runtime: check for DISPLAY instead of XDG_CURRENT_DESKTOP to check if linux machine is GUIless or not (#2373)

Signed-off-by: lucasew <[email protected]>

Author: lucasew

sdk/python/packages/flet-runtime/src/flet_runtime/utils.py

@@ -47,7 +47,7 @@ def is_linux_server():
             with open(p, "r") as file:
                 if "microsoft" in file.read():
                     return False  # it's WSL, not a server
-        return os.environ.get("XDG_CURRENT_DESKTOP") is None
+        return os.environ.get("DISPLAY") is None
     return False