gpui: Add truncate and text_ellipsis to TextStyle (#14850)

Release Notes:

- N/A

Ref issue #4996

## Demo

```
cargo run -p gpui --example text_wrapper 
```



https://github.com/user-attachments/assets/a7fcebf7-f287-4517-960d-76b12722a2d7

---------

Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

crates/gpui/Cargo.toml

@@ -178,3 +178,7 @@ path = "examples/input.rs"
 [[example]]
 name = "shadow"
 path = "examples/shadow.rs"
+
+[[example]]
+name = "text_wrapper"
+path = "examples/text_wrapper.rs"