Fix mechanoid emerge from water raid desyncs

[SokyranTheDragon]

The mechanoid "emerge from water" raids use the current map for spawning pawns, rathehr than the actually raided map. This is a bug/oversight in RimWorld itself, and may get fixed in the future.

Currently, this causes issues since checking for currently active map is non-deterministic, thus potentially spawning the mechanoids on different maps for each player.