wayland/outputmanagement: provide an error string if applying fails
And fail it with an error string if loading the ICC profile fails for any reason.
Draft because this bumps C++ version to 23, and I'm not sure if Neon supports it? Might need to do a poor man's std::expected
with a struct again if that's the case...
Depends on libraries/plasma-wayland-protocols!91 (merged), and is for kscreen!329 (merged)