Bump testbench 9.x minimum to ^9.2 for latestResponse fix

Version 9.1.4 made the $latestResponse static property optional,
which is required for PHPUnit 10 compatibility on prefer-lowest builds.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: aarondfrancis

composer.json

@@ -18,7 +18,7 @@
     "require-dev": {
         "laravel/pint": "^1.0",
         "mockery/mockery": "^1.6",
-        "orchestra/testbench": "^8.21|^9.0|^10.0",
+        "orchestra/testbench": "^8.21|^9.2|^10.0",
         "phpunit/phpunit": "^10.5|^11.0"
     },
     "autoload": {