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

crates/tasks_ui/src/lib.rs

@@ -66,6 +66,8 @@ pub fn init(cx: &mut AppContext) {
                                 cx,
                             );
                         }
+                    } else {
+                        toggle_modal(workspace, cx);
                     };
                 });
         },
@@ -76,17 +78,19 @@ pub fn init(cx: &mut AppContext) {
 fn spawn_task_or_modal(workspace: &mut Workspace, action: &Spawn, cx: &mut ViewContext<Workspace>) {
     match &action.task_name {
         Some(name) => spawn_task_with_name(name.clone(), cx),
-        None => {
+        None => toggle_modal(workspace, cx),
-            let inventory = workspace.project().read(cx).task_inventory().clone();
-            let workspace_handle = workspace.weak_handle();
-            let task_context = task_context(workspace, cx);
-            workspace.toggle_modal(cx, |cx| {
-                TasksModal::new(inventory, task_context, workspace_handle, cx)
-            })
-        }
     }
 }
 
+fn toggle_modal(workspace: &mut Workspace, cx: &mut ViewContext<'_, Workspace>) {
+    let inventory = workspace.project().read(cx).task_inventory().clone();
+    let workspace_handle = workspace.weak_handle();
+    let task_context = task_context(workspace, cx);
+    workspace.toggle_modal(cx, |cx| {
+        TasksModal::new(inventory, task_context, workspace_handle, cx)
+    })
+}
+
 fn spawn_task_with_name(name: String, cx: &mut ViewContext<Workspace>) {
     cx.spawn(|workspace, mut cx| async move {
         let did_spawn = workspace