Down arrowhead icons on compose page have no accessible name

[dankeck]

Checklist

• [X] I have used the search function to see if someone else has already submitted the same bug report.
• [X] I will describe the problem with as much detail as possible.

App version

8.0b1

Where did you get the app from?

Google Play

Android version

14

Device model

Pixel 5

Steps to reproduce

1. Start the Android TalkBack screen reader.
2. Open Thunderbird Beta.
3. Compose a new email message.
4. Use TalkBack to navigate to the down arrowhead icon next to the From field, or the icon next to the To field.

Expected behavior

TalkBack says the purpose of the button, such as "more" or "expand" or "additional fields".

Actual behavior

TalkBack says "unlabeled button" and does not convey the purpose of the button.

Logs

No response