Toggle tasks modal in task::Rerun, when no tasks have been scheduled (#11059)

Currently, when no tasks have been scheduled, the `task::Rerun` action
does nothing.
This PR adds a fallback, so when no tasks have been scheduled so far the
`task::Rerun` action toggles the tasks modal

https://github.com/zed-industries/zed/assets/471335/72f7a71e-cfa8-49db-a295-fb05b2e7c905

Release Notes:

- Improved the `task::Rerun` action to toggle the tasks modal when no
tasks have been scheduled so far
1af1a9e8b3Tim Masliuchenko committed on 4/26/2024, 3:56:34 PM· committed by GitHubparent8006f69
1 file changedLine totals unavailable