Use plist main binary for Rosetta audit

Currently `brew audit` only audits the first binary in a cask.
For example the cask `wiso-steuer-2024` contains multiple binaries in
`Contents/MacOS`:
- `btssysteminfo`
- `whilfe`
- `wmain24`

The first binary (some telemetry tool) is not the main binary and not
a universal binary, but the other two are. Given that `wmain24` is
defined as the main binary in the `Contents/Info.plist`, brew probably
should audit that binary rather than just checking the first one.

Library/Homebrew/cask/audit.rb

@@ -574,7 +574,11 @@ module Cask
               File.executable?(f) && !File.directory?(f) && !f.end_with?(".dylib")
             end
             add_error "No binaries in App: #{artifact.source}", location: cask.url.location if files.empty?
-            system_command("lipo", args: ["-archs", files.first], print_stderr: false)
+
+            main_binary = get_plist_main_binary(path)
+            main_binary ||= files.first
+
+            system_command("lipo", args: ["-archs", main_binary], print_stderr: false)
           when Artifact::Binary
             binary_path = path.to_s.gsub(cask.appdir, tmpdir)
             system_command("lipo", args: ["-archs", binary_path], print_stderr: true)
@@ -739,6 +743,17 @@ module Cask
       end
     end
 
+    sig { params(path: Pathname).returns(T.nilable(String)) }
+    def get_plist_main_binary(path)
+      return unless online?
+
+      plist_path = "#{path}/Contents/Info.plist"
+      return unless File.exist?(plist_path)
+
+      plist = system_command!("plutil", args: ["-convert", "xml1", "-o", "-", plist_path]).plist
+      plist["CFBundleExecutable"].presence
+    end
+
     sig { void }
     def audit_github_prerelease_version
       odebug "Auditing GitHub prerelease"