[Accessibility]: Added Narrator announcement to ListControl Focus
[Accessibility]: Added Narrator announcement to ListControl Focus

Issue:
- There's no narrator announcement when focusing menu suggestion items.

Changes:
- Added narrator announcement when focusing menu suggestion items.  Added the changes to ListControl.ts

Bug: 1346330
Change-Id: I5ec4357467fc7ce6da0e207c5d8c74b01694624c
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3780899
Reviewed-by: Michael Liao <00d75d81082fdf74688ec453c516b42f7cbf0f40@microsoft.com>
Reviewed-by: Benedikt Meurer <024a1e0af501338d11c3b837c6193d11c140d792@chromium.org>
Commit-Queue: Michael Liao <00d75d81082fdf74688ec453c516b42f7cbf0f40@microsoft.com>

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