collab ui: Fix notification windows on external monitors (#9817)

Sharing a project displays a notification (window) on every screen.
Previously there was an issue with the positioning of windows on all
screens except the primary screen.

As you can see here:


![image](https://github.com/zed-industries/zed/assets/53836821/314cf367-8c70-4e8e-bc4a-dcbb99cb4f71)

Now:


![image](https://github.com/zed-industries/zed/assets/53836821/42af9ef3-8af9-453a-ad95-147b5f9d90ba)

@mikayla-maki and I also decided to refactor the `WindowOptions` a bit. 
Previously you could specify bounds which controlled the positioning and
size of the window in the global coordinate space, while also providing
a display id (which screen to show the window on). This can lead to
unusual behavior because you could theoretically specify a global bound
which does not even belong to the display id which was provided.

Therefore we changed the api to this:
```rust
struct WindowOptions {
    /// The bounds of the window in screen coordinates
    /// None -> inherit, Some(bounds) -> set bounds.
    pub bounds: Option<Bounds<DevicePixels>>,

    /// The display to create the window on, if this is None,
    /// the window will be created on the main display
    pub display_id: Option<DisplayId>,
}
```

This lets you specify a display id, which maps to the screen where the
window should be created and bounds relative to the upper left of the
screen.

Release Notes:

- Fixed positioning of popup windows (e.g. when sharing a project) when
using multiple external displays.

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

crates/workspace/src/persistence/model.rs

@@ -6,7 +6,7 @@ use db::sqlez::{
     bindable::{Bind, Column, StaticColumnCount},
     statement::Statement,
 };
-use gpui::{AsyncWindowContext, Bounds, GlobalPixels, Model, Task, View, WeakView};
+use gpui::{AsyncWindowContext, Bounds, DevicePixels, Model, Task, View, WeakView};
 use project::Project;
 use std::{
     path::{Path, PathBuf},
@@ -69,7 +69,7 @@ pub(crate) struct SerializedWorkspace {
     pub(crate) id: WorkspaceId,
     pub(crate) location: WorkspaceLocation,
     pub(crate) center_group: SerializedPaneGroup,
-    pub(crate) bounds: Option<Bounds<GlobalPixels>>,
+    pub(crate) bounds: Option<Bounds<DevicePixels>>,
     pub(crate) fullscreen: bool,
     pub(crate) display: Option<Uuid>,
     pub(crate) docks: DockStructure,