tableau-*: use livecheck reference

[samford]

Important: Do not tick a checkbox if you haven’t performed its action. Honesty is indispensable for a smooth review process.

In the following questions <cask> is the token of the cask you're submitting.

After making any changes to a cask, existing or new, verify:

• The submission is for a stable version or documented exception.
• brew audit --cask --online <cask> is error-free.
• brew style --fix <cask> reports no offenses.

Additionally, if adding a new cask:

• Named the cask according to the token reference.
• Checked the cask was not already refused (add your cask's name to the end of the search field).
• brew audit --cask --new <cask> worked successfully.
• HOMEBREW_NO_INSTALL_FROM_API=1 brew install --cask <cask> worked successfully.
• brew uninstall --cask <cask> worked successfully.

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The various Tableau casks all contain an identical livecheck block that checks an upstream TableauAutoUpdate.xml file. The XML file only contains file information for Tableau Desktop, so that would suggest that these apps all use the same version if the in-app updater for each checks the same file.

Since the XML file lists information for Tableau Desktop, there's enough of a parent-child relationship between the tableau cask and the various tableau-* casks for us to simply use cask "tableau" in their livecheck blocks (instead of having to duplicate the same livecheck block in each). This will make it so that we only have to update the tableau livecheck block in the future (which may happen sooner or later, with regard to #191077 (review)).