Refreshing Cache

I run a self-hosted instance of Prefect 2.10.9 and have a flow that uses caching for most of its tasks (cache_key_fn=task_input_hash). Sometime (e.g. after re-deploying a flow after bug fixing) I want to manually start a flow run from the UI that ignores all cached data.

It seems I cannot set PREFECT_TASK_REFRESH_CACHE from within the flow. Any ideas how to solve the issue?