Common errors and warnings should be translated when displayed in the
GUI, but not translated when displayed elsewhere. The wallet method
CreateWalletFromFile does not know its caller, so this commit changes it
to return a bilingual_str to the caller.
This is a partial backport of Core PR18699 : https://github.com/bitcoin/bitcoin/pull/18699/commits/fae51a5c6f4270a1088e6295b10a8cc45988ae46