use more robust `is_mach_o_binary` from briefcase

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see here: https://github.com/beeware/briefcase/blob/1563842192f28a735401330f1d89178b08f749c9/src/briefcase/platforms/macOS/init.py#L295C1-L318

This would detect some of the files we are missing per issues like #5 #6 #7 .

Although obviously see also #2 .