Disabled message score button (for messages without spam headers) still shows previous score

[vali-um]

Describe the bug
On mails without Spam Headers the message score button gets greyed out but still shows icon and score of the previous message.

Reproduction steps
select mail A with spam headers -> message score button updated
select mail B without spam headers -> message score button greyed out but still contains values from mail A

Expected behavior
message score button content gets cleared

Thunderbird (please complete the following information):

• OS: Debian Linux
• Version: 115.12.0

Spam Score add-on (please complete the following information):

• Version: 1.4.1

Additional context
Patched manifest.json to allow installation