project_panel: Add Sticky Scroll (#33994)

Closes #7243

- Adds `top_slot_items` to `uniform_list` component to offset list
items.
- Adds `ToPosition` scroll strategy to `uniform_list` to scroll list to
specified index.
- Adds `sticky_items` component which can be used along with
`uniform_list` to add sticky functionality to any view that implements
uniform list.


https://github.com/user-attachments/assets/eb508fa4-167e-4595-911b-52651537284c

Release Notes:

- Added sticky scroll to the project panel, which keeps parent
directories visible while scrolling. This feature is enabled by default.
To disable it, toggle `sticky_scroll` in settings.

crates/ui/src/components.rs

@@ -30,6 +30,7 @@ mod scrollbar;
 mod settings_container;
 mod settings_group;
 mod stack;
+mod sticky_items;
 mod tab;
 mod tab_bar;
 mod toggle;
@@ -70,6 +71,7 @@ pub use scrollbar::*;
 pub use settings_container::*;
 pub use settings_group::*;
 pub use stack::*;
+pub use sticky_items::*;
 pub use tab::*;
 pub use tab_bar::*;
 pub use toggle::*;