consul: fix to remove outdated caveat

The caveat for the `-ui-dir` parameter is no longer correct as since 0.7
and above produce this warning if you try and use it:

```
==> If using Consul version 0.7.0 or later, the web UI is included in the
    binary so use ui to enable it
```

Using -agent -dev implies -ui and so the caveat produces an error trying
to start Consul.

As a result the `pkgshare.install` is superfluous and so that's gone
too.

Closes #15926.

Signed-off-by: ilovezfs <ilovezfs@icloud.com>

Formula/consul.rb

@@ -29,16 +29,9 @@ def install
       system "make"
       bin.install "bin/consul"
       zsh_completion.install "contrib/zsh-completion/_consul"
-      pkgshare.install "ui" => "web-ui"
     end
   end
 
-  def caveats; <<-EOS.undent
-    You can activate the UI by running
-    consul with `-ui-dir #{pkgshare}/web-ui`.
-    EOS
-  end
-
   plist_options :manual => "consul agent -dev -advertise 127.0.0.1"
 
   def plist; <<-EOS.undent