acp_thread: Fix panic when following acp agents across buffers (#40798)

Fixes ZED-2D7

Release Notes:

- N/A *or* Added/Fixed/Improved ...
854d1ec4dcLukas Wirth committed on 10/21/2025, 2:37:16 PM· committed by GitHubparent10b9ae5
2 files changedLine totals unavailable