[A11y] New item in bulleted list doesn't use custom announcement

[vhuseinova-msft]

Describe the bug RoosterJS provides a way to set a custom announcements for new items bulleted list (announcerStringGetter). But it looks like even when announcerStringGetter returns a value for announceListItemBullet, it is still not used by announcer.

To Reproduce Steps to reproduce the behavior:

1. Open Rooster JS demo web site
2. Click add bulleted list button
3. type some text
4. Press enter

5. Observe that Narrator/VoiceOver doesn't announce a custom announcement for announceListItemBullet

6. Open Rooster JS demo web site
7. Press "-" key and space key
8. type some text
9. Press enter
10. Observe that Narrator/VoiceOver doesn't announce a custom announcement for announceListItemBullet

Expected behavior The announceListItemBullet string returned in announcerStringGetter should be used to announce when a new bullet is added (in autoformatted list and when list is added with toggleBullet api)

Device Information

• OS: [e.g. iOS] MacOS
• Browser [e.g. chrome, safari] Edge
• Version [e.g. 22]

[vhuseinova-msft]

cc @BryanValverdeU