fix: add global scope declaration for $register in registers.php

PHPUnit's FileLoader::load() includes bootstrap files inside a function
scope. Without the global declaration, $register is created in local
scope and isn't accessible when other files (like resources.php) use
global $register to reference it.

app/init/registers.php

@@ -31,6 +31,7 @@ use Utopia\Queue;
 use Utopia\Registry\Registry;
 use Utopia\System\System;
 
+global $register;
 $register = new Registry();
 
 Http::setMode(System::getEnv('_APP_ENV', Http::MODE_TYPE_PRODUCTION));