mypy: check vllm/multimodal

Signed-off-by: Russell Bryant <rbryant@redhat.com>

Author: russellb

format.sh

@@ -115,7 +115,7 @@ run_mypy vllm/executor
 run_mypy vllm/logging
 run_mypy vllm/lora
 run_mypy vllm/model_executor
-#run_mypy vllm/multimodal
+run_mypy vllm/multimodal
 run_mypy vllm/platforms
 run_mypy vllm/plugins
 run_mypy vllm/prompt_adapter