metrolyrics: fix parser after metrolyrics changes
metrolyrics: fix parser after metrolyrics changes

Metrolyrics now include `class="js-lyric-text"` in the div for lyrics
and this patch just ignore it.

Also remove `<br>` noise that was introduced recently.

https://bugzilla.gnome.org/show_bug.cgi?id=759109

grilofw/grilo-plugins,MikePetullo/grilo-plugins,jasuarez/grilo-plugins,GNOME/grilo-plugins,MikePetullo/grilo-plugins,MikePetullo/grilo-plugins,GNOME/grilo-plugins,grilofw/grilo-plugins,jasuarez/grilo-plugins