Fix #140416: Crash when undoing adding camera background movie clip

Fix free_movieclips_textures.
Release movieclips at the end of draw.
(Same behavior as Overlay Legacy)

source/blender/draw/engines/overlay/overlay_private.hh

@@ -892,6 +892,7 @@ struct Resources : public select::SelectMap {
     this->depth_in_front_alloc_tx.release();
     this->color_overlay_alloc_tx.release();
     this->color_render_alloc_tx.release();
+    free_movieclips_textures();
   }
 
   ThemeColorID object_wire_theme_id(const ObjectRef &ob_ref, const State &state) const
@@ -999,6 +1000,7 @@ struct Resources : public select::SelectMap {
     for (MovieClip *clip : bg_movie_clips) {
       BKE_movieclip_free_gputexture(clip);
     }
+    bg_movie_clips.clear();
   }
 
   static float vertex_size_get()