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/terminal_view/src/terminal_element.rs

@@ -667,6 +667,7 @@ impl Element for TerminalElement {
                     line_height: line_height.into(),
                     background_color: Some(theme.colors().terminal_background),
                     white_space: WhiteSpace::Normal,
+                    truncate: None,
                     // These are going to be overridden per-cell
                     underline: None,
                     strikethrough: None,