[Snackbar] Screen reader not reading a snackbar when triggered from a button within a dialog

Duplicates

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Latest version

• I have tested the latest version

Current behavior 😯

When snackbars are triggered from a button within a dialog they are not read by the screen reader.

Expected behavior 🤔

When snackbars are triggered from a button within a dialog they should be read by the screen reader.

Steps to reproduce 🕹

Steps

1. User launches NVDA or JAWS
2. User opens https://codesandbox.io/s/dialog-snackbar-not-accessible-gzl5o?file=/demo.js in Chrome, Firefox or Edge
3. User clicks the "OPEN DIALOG" button and the dialog is launched
4. User clicks the "OPEN SNACKBAR" button within the dialog and the snackbar is launch
5. The screen reader does not read the snackbar and the user of the assistive technology is unaware the snackbar exists

Context 🔦

We are building forms and flows that combine the dialog and snackbar components. We need some none intrusive alerts that inform users their task was successful. Snackbars fit our need but are not accessible when triggered from a button within a dialog.

Your environment 🌎

  Don't forget to mention which browser you used.
  Output from `npx @mui/envinfo` goes here.

Start with the linked CodeSandbox reproduction in demo.js and reproduce the issue using NVDA or JAWS in a supported browser. Trace how the Snackbar is triggered from the dialog, then verify that the snackbar is announced when opened from the dialog without breaking the dialog interaction.