85973bcc44f60fe3bbc952557ebf578dd4c475d2 When BIP70 is disabled, get PaymentRequest merchant using string search (Andrew Chow)
Pull request description:
The merchant name is stored in the X.509 certificate embedded in a PaymentRequest. Use some string searching to locate it so that it can be shown to the user in the transaction details when BIP70 support was not configured. An additional notice is added to the merchant string that indicates the certificate was not verified. When BIP70 is enabled, the certificate would be verified and the merchant name not shown if the certificate was invalid.
Backport of Core PR16852