Prefer family name in fonts' names table

[timothyqiu]

Currently, family_name is used as a font's name. This field is an ASCII string, but

In case the font doesn't provide a specific family name entry, FreeType tries to synthesize one, deriving it from other name entries.

FreeType converts non-ASCII characters into question marks ("?") in this process, resulting in unreadable names for some fonts.

This PR prioritizes reading SFNT names (the name table of TrueType and OpenType fonts) to avoid possible question marks. English (US) is still preferred, so it's mostly compatible.

Among possible encodings, UTF-16 is the most common one that Godot's String supports. But it's always in big endian, so I added an extra parameter to String::parse_utf16() to specify the endianness to use when no BOM is present.

[timothyqiu]

Added the same logic in TextServerFallback.

Using hb_ot_name_get_utf32 in TextServerAdvanced does make decoding easier 🎉

[timothyqiu]

Added the check for BIG_ENDIAN_ENABLED inside String::parse_utf16().

[akien-mga]

Thanks!