Fix zap regression introduced in 6500fa1; ref #21583 (#21607)

This PR fixes an issue with 6500fa1, in which the (internal) installer API was refactored in preparation for the big change. That refactoring missed one case, causing `zap` to break; see #21583.

There are **no tests** included with this fix due to pre-existing coverage issues. Test will follow in a separate commit.

lib/hbc/installer.rb

@@ -304,7 +304,7 @@ def zap
     uninstall_artifacts
     if Hbc::Artifact::Zap.me?(@cask)
       ohai "Dispatching zap stanza"
-      Hbc::Artifact::Zap.new(@cask, @command).zap_phase
+      Hbc::Artifact::Zap.new(@cask, command: @command).zap_phase
     else
       opoo "No zap stanza present for Cask '#{@cask}'"
     end