Test: next edit suggestions with a screen reader

[meganrogge]

Refs #246922, #246921, #230322

• Windows
• macOS
• anyOS

Complexity: 3

Authors: @meganrogge, @hediet

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1. Enable a screen reader and navigate through the NES experience.
2. Confirm that when a Next Edit Suggestion is available, it is announced with both an sound and an aria alert announcement labeled "Next Edit Suggestion".
3. Verify that those signals can be configured using the setting accessibility.signals.nextEditSuggestion.
4. Open the Accessible View using Alt+F2:
   • Confirm that accessibility signals are played for added (+) and deleted (-) lines.
5. Apply the suggestion and confirm that it occurred.