Add the ability for tasks to target the center pane (#22004)

Closes #20060
Closes #20720
Closes #19873
Closes #9445

Release Notes:

- Fixed a bug where tasks would be spawned with their working directory
set to a file in some cases
- Added the ability to spawn tasks in the center pane, when spawning
from a keybinding:

```json5
[
  {
    // Assuming you have a task labeled "echo hello"
    "ctrl--": [
      "task::Spawn",
      { "task_name": "echo hello", "target": "center" }
    ]
  }
]
```

crates/tasks_ui/src/lib.rs

@@ -11,6 +11,7 @@ mod modal;
 mod settings;
 
 pub use modal::{Rerun, Spawn};
+use zed_actions::TaskSpawnTarget;
 
 pub fn init(cx: &mut AppContext) {
     settings::TaskSettings::register(cx);
@@ -53,6 +54,7 @@ pub fn init(cx: &mut AppContext) {
                                             task_source_kind,
                                             &original_task,
                                             &task_context,
+                                            Default::default(),
                                             false,
                                             cx,
                                         )
@@ -89,7 +91,8 @@ 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).detach_and_log_err(cx),
+        Some(name) => spawn_task_with_name(name.clone(), action.target.unwrap_or_default(), cx)
+            .detach_and_log_err(cx),
         None => toggle_modal(workspace, cx).detach(),
     }
 }
@@ -119,6 +122,7 @@ fn toggle_modal(workspace: &mut Workspace, cx: &mut ViewContext<'_, Workspace>)
 
 fn spawn_task_with_name(
     name: String,
+    task_target: TaskSpawnTarget,
     cx: &mut ViewContext<Workspace>,
 ) -> AsyncTask<anyhow::Result<()>> {
     cx.spawn(|workspace, mut cx| async move {
@@ -160,6 +164,7 @@ fn spawn_task_with_name(
                     task_source_kind,
                     &target_task,
                     &task_context,
+                    task_target,
                     false,
                     cx,
                 );

crates/tasks_ui/src/modal.rs

@@ -68,7 +68,7 @@ impl TasksModalDelegate {
         };
         Some((
             source_kind,
-            new_oneshot.resolve_task(&id_base, &self.task_context)?,
+            new_oneshot.resolve_task(&id_base, Default::default(), &self.task_context)?,
         ))
     }
 
@@ -684,6 +684,7 @@ mod tests {
 
         cx.dispatch_action(Spawn {
             task_name: Some("example task".to_string()),
+            target: None,
         });
         let tasks_picker = workspace.update(cx, |workspace, cx| {
             workspace