get Fallback Font Bytes
Retrieves the byte array of a fallback font specified by optional font options.
This function combines the functionality of getFallbackFont and getFontBytes to fetch the bytes of a font that matches the provided options. If no specific options are provided, default settings are used. This is useful when direct byte-level access to a font file is required, such as for sending font data over a network or loading it into a custom rendering system.
Return
A ByteArray containing the font's data, or null if no suitable font is found or if there is an error accessing the font file.
Parameters
opts
Optional Fonts.FontOpts specifying the desired font characteristics. If not provided, default options are used.