Add TJS (Tajikistani somoni) to CurrencyEnum

Please add TJS (Tajikistani somoni, ISO 4217) to CurrencyEnum.

We create supplier bills via POST /v1/bills/. Bills issued in Tajikistani somoni are rejected with HTTP 400:

"TJS" is not a valid choice (attr: currency).

TZS in the current enum is the Tanzanian shilling, not the Tajikistani somoni. We need to record these bills in TJS rather than convert them to USD.

CurrencyEnum: https://developer.wafeq.com/reference/currencyenum