Shrink agent terminals on clear (#62504)

Makes agent panel a bit more ergonomic: on terminal reset, user clear
(demonstrated on videos), etc. shrink its size down.

Before:


https://github.com/user-attachments/assets/ce722f39-0ac7-4b86-9ff6-ecd8e327cc43

After:


https://github.com/user-attachments/assets/f1825c9c-e52e-4d08-ac95-1403a6b0b1ea


Release Notes:

- Improved terminal behavior in agent panel on clear