cmd/list: fix duplicate casks when symlinks exist

When a cask is renamed (e.g. logi-options-plus to logi-options+),
Homebrew creates a symlink in the Caskroom directory. Currently,
`brew list --cask` shows both the original and symlinked cask as
separate entries. This patch modifies the listing logic to resolve
symlinks and show only unique casks.

Fixes Homebrew#18849

Library/Homebrew/cmd/list.rb

@@ -214,7 +214,15 @@ def filtered_list
       sig { void }
       def list_casks
         casks = if args.no_named?
-          Cask::Caskroom.casks
+          cask_paths = Cask::Caskroom.path.children.map do |path|
+            if path.symlink?
+              real_path = path.realpath
+              real_path.basename.to_s
+            else
+              path.basename.to_s
+            end
+          end.uniq
+          cask_paths.map { |name| Cask::CaskLoader.load(name) }
         else
           filtered_args = args.named.dup.delete_if do |n|
             Homebrew.failed = true unless Cask::Caskroom.path.join(n).exist?