Fix: Cached distortion grids are not reset

The patch that introduced distortion grids forgot to reset them in the
static cache manager.

source/blender/compositor/realtime_compositor/intern/static_cache_manager.cc

@@ -15,6 +15,7 @@ void StaticCacheManager::reset()
   cached_masks.reset();
   smaa_precomputed_textures.reset();
   ocio_color_space_conversion_shaders.reset();
+  distortion_grids.reset();
 }
 
 }  // namespace blender::realtime_compositor