[SpeedDial] Support action slot object refs

[OskarEichler]

What changed

• Fixes SpeedDialAction slotProps.fab.ref when it is an object ref such as React.createRef(); the current implementation calls the ref as a function and throws.
• Preserves cleanup functions returned by React 19 callback refs, allowing React to run the callback's cleanup instead of falling back to a null callback.
• No public API is removed or renamed. This is a backward-compatible behavior fix.

The wrapper now delegates non-function refs to MUI's existing setRef helper and returns callback-ref cleanup values.

Verification

• Reproduced the object-ref crash against the unmodified base.
• Reproduced the missing React 19 callback cleanup against the unmodified base.
• Verified both cases after the fix.
• pnpm test:unit run SpeedDial --project 'node:@mui/material'
• pnpm -F @mui/material typescript
• Targeted ESLint and Prettier checks.
• Full pnpm release:build.
• Full Material Node unit suite: 179 passed / 4 skipped files; 4,712 passed / 759 skipped tests.

The browser test project was not run locally because Playwright Chromium is not installed in this checkout.

Contribution

• I have followed the contributing guide.

This change and PR description were prepared with OpenAI Codex, then self-reviewed and verified locally. No independent human review has occurred yet.

[code-infra-dashboard]

Deploy preview

https://deploy-preview-49056--material-ui.netlify.app/

Bundle size

Bundle	Parsed size	Gzip size
@mui/material	🔺+36B(+0.01%)	🔺+15B(+0.01%)
@mui/lab	0B(0.00%)	0B(0.00%)
@mui/private-theming	0B(0.00%)	0B(0.00%)
@mui/system	0B(0.00%)	0B(0.00%)
@mui/utils	0B(0.00%)	0B(0.00%)

Details of bundle changes

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