[orca-list] Regression in Orca 3.30: Flat review no longer reads buttons to accept, refuse a meeting invitation

[Alex ARNAUD <alexarnaud hypra fr>]

Hello all,

Environment:
- Debian Stretch
- Orca master
- Both Thunderbird 52 and 60

I've a blind businessman that has reported to me that he is not longer 
able to reply to meeting invitation with the latest update to Orca 3.30 
on the same Thunderbird version (on his computer it's Thunderbird 52).

Steps to reproduce:
1) Open Thunderbird

2) Enable the Lightning extension to have the support of agenda/calendar

3) Link an lightning agenda to your mail to see the button accept, 
refuse, etc. To do that go on the Lightning tab ctrl+shift+c, do a right 
click on an agenda and select property and verify a mail is linked to 
the agenda

4) Open an invitation to a meeting (it's a mail containing the invitation)

5) Use flat review to go to the line with the button to accept or refuse 
an invitation

Result in Orca master:
Orca says "This message contains a invitation button button button" 
(Here in French it's "Ce message contient une invitation button button 
button" because Thunderbird is in french and Orca in C locale, I'm unabl 
to have Thunderbird in C locale, I don't know why)

Result in 3.28:
Orca says "This message contains a invitation Accept..."  (Here in 
French "This message contains a invitation Accept Accepter 
provisoirement Refuser")

In 3.30 the button state is announced but not the label whereas in 3.28 
the label is announced but not the type of the element, here button.

You could find a debug log of Orca master here:
https://framabin.org/p/?cb6b437be13d50a8#vphwo262vW4xxpGAQx913/cfcT6mOgALLKaSr+391u8=

You could find a debug log of 3.28 here:
https://framabin.org/p/?308146ed249c3504#Vniuxl5gz1WfuSP0YWYNtuHc3y3frnvXxVU3rEy3nvU=

Best regards,
Alex.