remove useless ext-json requirement

Author: garak

composer.json

@@ -14,7 +14,6 @@
         "php": ">=8.2",
         "ext-ctype": "*",
         "ext-iconv": "*",
-        "ext-json": "*",
         "ext-mbstring": "*",
         "league/flysystem": "^3",
         "league/flysystem-read-only": "^3",