Fix zsh completions for upgrade and reinstall

[muneebmahmed]

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#10410 fixed my previous issue #10409, however it also resulted in the upgrade completion to list every cask, not just the outdated or installed ones. I noticed the same behavior for brew reinstall as well. This fixes those completions to only show installed/outdated casks.

I think this PR might become unnecessary due to #10403, but I created this one anyway in case that one does not get merged soon.

[MikeMcQuaid]

Thanks again @muneebmahmed!