[0.4.x] libvisual + libvisual-plugins: Mass-fix typo "[Tt]ransparant" once more

[hartwork]

git grep -l Transparant | xargs sed 's,Transparant,Transparent,g' -i
git grep -l transparant | xargs sed 's,transparant,transparent,g' -i

Thanks to @eribertomota :+1: