support snes satellaview roms - use alternative header offset

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Kroko
There are differences in the header of BS-X games, e.g. the map mode is in 0xFFD8 not 0xFFD5.
https://wiki.superfamicom.org/bs-x-satellaview-header

THATS why it doesnt work in Diz. we need to look at another header location when we're auto-detecting the ROM on import.

[binary1230]

probably need to update this here: https://github.com/IsoFrieze/DiztinGUIsh/blob/b0d4bc69a4e264700ebeffe94b3ea337c28739e8/Diz.Core/util/RomUtil.cs#L251