assistant2: Truncate context pill labels (#26721)

To solve a problem that mostly happens if the pill is of kind `Thread`
and the corresponding thread has a super long title.

<img
src="https://github.com/user-attachments/assets/4ee8038d-9467-41a9-9b30-76019d0b9c0b"
width="500px"/>

Release Notes:

- N/A
2183fc674dDanilo Leal committed on 3/13/2025, 7:56:49 PM· committed by GitHubparent0ad5979
1 file changedLine totals unavailable