Fix T88885: Circle select deselects first selections after moving cursor

`is_active_prev` is always set after the first operation.
But this was not the case with `wait_for_input` `false`.

source/blender/windowmanager/intern/wm_gesture_ops.c

@@ -316,6 +316,7 @@ int WM_gesture_circle_invoke(bContext *C, wmOperator *op, const wmEvent *event)
   if (gesture->wait_for_input == false) {
     gesture->is_active = true;
     gesture_circle_apply(C, op);
+    gesture->is_active_prev = true;
   }
 
   /* add modal handler */