This lead to wrong, stretched UVs regardless of the ON/OFF state of
"Correct Aspect" option (some code in the operator respected this
setting properly, whereas it was hardcoded in another part).

Before rB9296ba867462, uvedit_pack_islands_multi was always called
with correct_aspect = false for the UnwrapOptions.
After rB9296ba867462, ED_uvedit_pack_islands_multi was always called
with correct_aspect = true for the UVPackIsland_Params.

Both seem wrong [in that they do not take the operator setting into
account]. Now respect that setting [same as the following
uv_map_clip_correct_multi does as well btw.]

Now results match 2.90 [where this was still python] perfectly.