expanding ellipses text in agent session view doesn't work

[eleanorjboyd]

while verifying https://github.com/microsoft/vscode/issues/281149 I found that expanding the agent sessions view for text with ellipses (the top item), it will not expand the text past the initial ellipses placement. The shrinking does work to move the ellipses up

https://github.com/user-attachments/assets/5b3d3b4e-064a-42af-a75e-900bf2dc1244