gpui: Rework overlay element (#9911)

There was a problem using deferred draws with `overlay` and tooltips at
the same time.

The `overlay` element was removed and was split up into two separate
elements
- `deferred`
- `anchored` - Mimics the `overlay` behavior but does not render its
children as deferred

`tooltip_container` does not defer its drawing anymore and only uses
`anchored`.

/cc @as-cii 


Release Notes:
- Fixed tooltip for the recent projects popover not showing anymore

---------

Co-authored-by: Antonio <antonio@zed.dev>

crates/ui/src/components/tooltip.rs

@@ -1,4 +1,4 @@
-use gpui::{overlay, Action, AnyView, IntoElement, Render, VisualContext};
+use gpui::{anchored, Action, AnyView, IntoElement, Render, VisualContext};
 use settings::Settings;
 use theme::ThemeSettings;
 
@@ -90,8 +90,8 @@ pub fn tooltip_container<V>(
     f: impl FnOnce(Div, &mut ViewContext<V>) -> Div,
 ) -> impl IntoElement {
     let ui_font = ThemeSettings::get_global(cx).ui_font.family.clone();
-    overlay().child(
-        // padding to avoid mouse cursor
+    // padding to avoid mouse cursor
+    anchored().child(
         div().pl_2().pt_2p5().child(
             v_flex()
                 .elevation_2(cx)