searchProvider: Fix deprecation fixes
searchProvider: Fix deprecation fixes

- `ByteArray` did not get imported and was missing.
- `String.prototype.toUpperCase` cannot be passed directly to `map`.

Fixes https://gitlab.gnome.org/GNOME/gnome-characters/issues/49

GNOME/gnome-characters,GNOME/gnome-characters,GNOME/gnome-characters,GNOME/gnome-characters,GNOME/gnome-characters