agent_ui: Wrap long `ask_user` options (#63656)

# Objective

Fixes #62955

Long `ask_user` option labels are currently truncated with an ellipsis,
which can hide part of the response text.

## Solution

Remove truncation from the shared elicitation option label so it uses
the label's default multiline wrapping. This affects both single- and
multi-select options without changing selection behavior.

## Testing

- `cargo fmt --all -- --check`
- `cargo test -p agent_ui -- --nocapture` — 429 passed, 0 failed
- `cargo build -j 2 -p zed --bin zed`
- Manually reproduced the issue using a long `ask_user` option label.
- Verified that the complete label wraps without an ellipsis at wide and
narrow panel widths.

---

Release Notes:

- Fixed long `ask_user` options being truncated instead of wrapping.
73ee8fa038Chara committed on 9/3/2026, 1:24:32 PM· committed by GitHubparented8d600
1 file changedLine totals unavailable