Use symmetric padding in signature popovers (#27734)

Release Notes:

- Fixed padding issue with the signature popovers

------

Before:
<img width="372" alt="Screenshot 2025-03-29 at 20 30 39"
src="https://github.com/user-attachments/assets/36d1555d-bccb-4fca-b6ad-514cf11d024f"
/>

After:
<img width="375" alt="Screenshot 2025-03-29 at 20 31 13"
src="https://github.com/user-attachments/assets/6566d0e9-9dae-47dc-bfa0-526bf35f3cf0"
/>
0079771e34Stanislav Alekseev committed on 4/1/2025, 12:14:33 PM· committed by GitHubparentd1db6d6
1 file changedLine totals unavailable