[Suggestion] Skip empty strings in IFS="¤" loops

[danonb]

In the context of distrobox-assemble and depending on a user's shell environment, the IFS="¤" delimiter can result in an empty string within the proceeding loop.

I suggest building in the ability to detect and skip such situations.

This issue would be apparent for cases where fields like 'volume' are described on multiple lines of an *.ini file.

[danonb]

    if [ -n "${volume}" ]; then
        IFS="¤"
        for vol in ${volume}; do
            [ -z "${vol}" ] && continue # Skip empty fields      
            result_command="${result_command} --volume $(sanitize_variable "${vol}")"
        done
    fi