LibLocale+LibJS: Make relative time format APIs infallible

These APIs only perform small allocations, and are only used by LibJS.
Callers which could only have failed from these APIs are also made to
be infallible here.

Userland/Libraries/LibLocale/RelativeTimeFormat.cpp

@@ -53,6 +53,6 @@ StringView time_unit_to_string(TimeUnit time_unit)
     }
 }
 
-ErrorOr<Vector<RelativeTimeFormat>> __attribute__((weak)) get_relative_time_format_patterns(StringView, TimeUnit, StringView, Style) { return Vector<RelativeTimeFormat> {}; }
+Vector<RelativeTimeFormat> __attribute__((weak)) get_relative_time_format_patterns(StringView, TimeUnit, StringView, Style) { return {}; }
 
 }