Fixes:#10933 context swatch crash issue

Issue #10933 (closed) wasn't actually due to zoomfactor. Whenever the keys "0" or "9" were pressed, a keyevent would trigger and result in an action. Now that action would call the function context_swatch_foreground_cmd_callback() Which in turn, called context_select_color() function, which would free the GeglColor color variable. But we were also freeing it in the context_swatch_foreground_cmd_callback() function, so it would result in a segmentation fault. So, stopping one of the g_object_unref(color) function calls did the trick. The keys also work as desired now.