Fix T101402: EEVEE: Wrong Volume transforms

Ensure VolumeUniformPool uses is always incremented when retrieving a buffer in alloc().
Otherwise the same buffer will be retrieved for more than one object when incrementing the pool size.

Reviewed By: fclem

Maniphest Tasks: T101402

Differential Revision: https://developer.blender.org/D16607

source/blender/draw/intern/draw_volume.cc

@@ -56,7 +56,6 @@ struct VolumeUniformBufPool {
     if (used >= ubos.size()) {
       VolumeInfosBuf *buf = new VolumeInfosBuf();
       ubos.append(buf);
-      return buf;
     }
     return ubos[used++];
   }