On master (5f44c5c428b696af4214b2519cb2bbeb0e4a1027) an attempt to load an external signer wallet using Bitcoin Core compiled without external signer support fails with the following log messages:
2022-02-20T19:01:11Z [qt-walletctrl] Using SQLite Version 3.31.1
2022-02-20T19:01:11Z [qt-walletctrl] Using wallet /home/hebasto/.bitcoin/testnet3/wallets/coldcard-0220
2022-02-20T19:01:11Z [qt-walletctrl] init message: Loading wallet…
2022-02-20T19:01:11Z [qt-walletctrl] [coldcard-0220] Error: External signer wallet being loaded without external signer support compiled
2022-02-20T19:01:11Z [qt-walletctrl] [coldcard-0220] Releasing wallet
While log messages are good, a message in the GUI window is completely misleading:

This PR fixes this issue:
