fix: pushCS should not be a GF (#6571)

Co-authored-by: elecpower <elecpower@users.noreply.github.com>

radio/src/gui/gui_common.cpp

@@ -678,6 +678,11 @@ bool isAssignableFunctionAvailable(int function, bool modelFunctions)
     case FUNC_TEST:
       return false;
 #endif
+#if defined(FUNCTION_SWITCHES) || defined(CFN_ONLY)
+    case FUNC_PUSH_CUST_SWITCH:
+      return modelFunctions;
+#endif
+
     default:
       return true;
   }