test: bump behat acceptance test dependencies (#435)

Change the PHP version for running Behat to 8.3
Update the version of Behat and its dependencies that is used.
Convert the Behat config from YML to a PHP file, similar to
what was done in core recently.

Author: phil-davis

composer.json

@@ -15,7 +15,7 @@
     "php": ">=8.3"
   },
   "require-dev": {
-    "bamarni/composer-bin-plugin": "^1.8",
+    "bamarni/composer-bin-plugin": "^1.9",
     "roave/security-advisories": "dev-latest"
   },
   "extra": {