refactor: Replace std::optional<bilingual_str> with util::Result
https://github.com/bitcoin/bitcoin/pull/25977/commits/8aa8f73adce72e1ae855b43413c1f65504423cb7
Add nodiscard where ignoring a Result return type is an error
https://github.com/bitcoin/bitcoin/pull/27774/commits/dddde27f6fbcff7cdb31f7138efc5d8363537b03
fix includes for touched header files (iwyu)
https://github.com/bitcoin/bitcoin/pull/27774/commits/fa5680b7520c340952239c4e25ebe505d16c7c39
This is a partial backport of core#25977 and core#27774