Screen reader does not convey confirmation feedback after successfully adding 'Key' and 'Value' to the table present in the Request headers tab.

[ElinorW]

Describe the bug
If there is no notification of events relevant to user interactions, changes in the component’s state(s), value, name, description, or boundary it would be difficult for the platforms that provide Accessibility APIs, and would in turn affect the screen reader dependent users to determine the information of any new page , new dialog box etc.

To Reproduce

1. Launch Narrator.
2. Open the URL in Anaheim edge dev browser.
3. Navigate to 'Request headers' tab present in the right side of the pane and activate it. 'Request headers' section will open.
4. Navigate and fill required details in the 'Key' and 'Value' edit box.
5. Navigate to the 'Add' button and activate it using enter key. Values of the 'Key' and 'Value' edit boxes gets successfully added in the table.
6. Observe the issue.

Actual behaviour
Screen reader does not convey confirmation feedback after successfully adding 'Key' and 'Value' values to the table present in the Request headers tab.

Expected behaviour
Screen reader should convey confirmation feedback after successfully adding 'Key' and 'Value' to the table present in the Request headers tab.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Win 10 Version 2004 (OS Build 20277.1)
• URL: https://developer.microsoft.com/en-us/graph/graph-explorer
• Browser: Anaheim Edge Dev Version 89.0.731.0 (Official build) dev (64-bit)
• Screen Reader: Narrator

Additional context

1. Same issue is repro with NVDA.
2. Same issue is repro on activating Delete button present in this table under Request header tab.
3. Same issue is repro on successfully activating 'Minimize Sidebar' button.
4. This issue is repro for every actionable item that happened successfully present throughout the URL.
   AB#7606