Fix MuonCaloTagAlg tool config

Trying to fix ATLASRECTS-7384. Not sure why it did not work before, but it was anyways a bit messy. Maybe the public tool needs to be added before adding to the fragment?

Note that ToolHandleArray still behaves strangely. It looks private but it requires a public tool. @wlampl, @fwinkl, @leggett, @jchapman any idea?

Do we ever even need an array here?

Tagging also @jojungge, @emoyse, @tsulaia