system_config: don't print path to curl shim

See discussion at #12191.

Library/Homebrew/system_config.rb

@@ -130,7 +130,7 @@ module SystemConfig
       out, = system_command(curl_executable, args: ["--version"], verbose: false)
 
       if /^curl (?<curl_version>[\d.]+)/ =~ out
-        "#{curl_version} => #{curl_executable}"
+        "#{curl_version} => #{curl_path}"
       else
         "N/A"
       end

Library/Homebrew/utils/curl.rb

@@ -22,6 +22,10 @@ module Utils
       @curl_executable ||= HOMEBREW_SHIMS_PATH/"shared/curl"
     end
 
+    def curl_path
+      @curl_path ||= Utils.popen_read(curl_executable, "--homebrew=print-path").chomp.presence
+    end
+
     sig {
       params(
         extra_args:      T.untyped,