fix: enable to run natively in wayland

Incorporated from this v2 change:
wailsapp#1811

Author: stendler

v3/pkg/application/application_linux.go

@@ -27,7 +27,9 @@ import (
 func init() {
 	// FIXME: This should be handled appropriately in the individual files most likely.
 	// Set GDK_BACKEND=x11 if currently unset and XDG_SESSION_TYPE is unset, unspecified or x11 to prevent warnings
-	_ = os.Setenv("GDK_BACKEND", "x11")
+	if os.Getenv("GDK_BACKEND") == "" && (os.Getenv("XDG_SESSION_TYPE") == "" || os.Getenv("XDG_SESSION_TYPE") == "unspecified" || os.Getenv("XDG_SESSION_TYPE") == "x11") {
+		_ = os.Setenv("GDK_BACKEND", "x11")
+	}
 }
 
 type linuxApp struct {