[UI Feature] "Rerun" button for sub-workflow.

### Motivation: Why do you think this is important?

When a workflow triggers sub-workflows, it is only possible to rerun the parent workflow from the UI. A button to rerun individual workflows would be nice.
A workaround for this is launching sub-workflows as launch plans, which create new executions that are rerunnable.
More info here: https://github.com/flyteorg/flyte/issues/5852

### Goal: What should the final outcome look like, ideally?

A button to rerun a sub-workflow

### Propose: Link/Inline OR Additional context

https://github.com/flyteorg/flyte/issues/5852

### Are you sure this issue hasn't been raised already?

- [X] Yes

### Have you read the Code of Conduct?

- [X] Yes

Start by tracing the existing UI action that reruns a parent workflow and review the linked issue 5852 for context on sub-workflow executions. Done means the UI offers a rerun button for an individual sub-workflow and successfully starts that workflow again.

Written by the indexing model from the issue text.