Reimplement Joomla 4.3 fix for portable-utf8 dependency (#40396)

Author: HLeithner

composer.json

@@ -98,7 +98,8 @@
         "lcobucci/jwt": "^4.2.1",
         "web-token/signature-pack": "^3.1.2",
         "phpseclib/bcmath_compat": "^2.0.1",
-        "jfcherng/php-diff": "^6.10.11"
+        "jfcherng/php-diff": "^6.10.11",
+        "voku/portable-utf8": "6.0.12 as 5.4.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^9.6.6",