UI bug: "Password OK" green confirmation bar is visually cut off during account setup

[n9n6nd6vbv]

Product: Thunderbird Daily
Version: 139.0a1 (2025-04-11) (64-bit)
Platform: macOS 15.4 (24E248)
Component: Account Setup
Email Provider: iCloud

Steps to Reproduce:

1. Launch Thunderbird Daily 139.0a1 on macOS 15.4.

2. Go to Account Setup.

3. Enter an existing iCloud email address and password.

4. Wait for Thunderbird to verify the credentials.

Expected Result: After the password is accepted, the confirmation UI (e.g., "Password OK" in green) should be clearly and fully visible.

Actual Result: The "Password OK" green confirmation bar is cut off halfway, making it appear visually broken or incomplete.

Screenshot:

[siffemcon]

You should report it at https://bugzilla.mozilla.org/enter_bug.cgi/.