Add support for Baidu ICCIDs (which have letters in them), e.g. 898604B719227100nnnn

[coderbyheart]

TIL: the Chinese telco Baidu decided to break the e.118 standard which defines the identifiers for SIM cards (ICCID) in order to be able to encode custom data instead of using it as a true serial number.
https://www.xingsuyun58.com/907996.html

Full details here: https://baike.baidu.com/item/iccid/5181544

The letter is used to designate segments (which group operators).

Example: 898604B719227100nnnn (n is an integer)