Fix: Send giftcard emails when the currency code is not set (RTC-33422)

When the currency code of a giftcard is not set, sending an email works correctly.

Email template for reminding customer (RTC-31612)

The RemindPIN giftcard email template type is renamed to Resend, and will be used for resend and recharge distributions.

Export to Excel (RTC-33595)

Giftcards transactions' export to Excel works properly when excelBlobStorageSasConnectionString parameter is set up.

Invalid validation requests (RTC-33413)

The GiftCard/Get requests return proper error messages if request parameters were invalid.