Fix psalm error

Author: alcaeus

src/Operation/DropSearchIndex.php

@@ -54,11 +54,13 @@ public function __construct(private string $databaseName, private string $collec
     /**
      * Execute the operation.
      *
+     * TODO PHP 8.2: Change return type to null
      * @see Executable::execute()
      * @throws UnsupportedException if write concern is used and unsupported
      * @throws DriverRuntimeException for other driver errors (e.g. connection errors)
+     * @return null
      */
-    public function execute(Server $server): Cursor
+    public function execute(Server $server): mixed
     {
         $cmd = [
             'dropSearchIndex' => $this->collectionName,
@@ -70,12 +72,14 @@ public function execute(Server $server): Cursor
         }
 
         try {
-            return $server->executeCommand($this->databaseName, new Command($cmd));
+            $server->executeCommand($this->databaseName, new Command($cmd));
         } catch (CommandException $e) {
             // Drop operations are idempotent. The server may return an error if the collection does not exist.
             if ($e->getCode() !== self::ERROR_CODE_NAMESPACE_NOT_FOUND) {
                 throw $e;
             }
         }
+
+        return null;
     }
 }