[material-ui][Select] Fix to show notched outline when displayEmpty

[ZeeshanTamboli]

• I have followed (at least) the PR section of the contributing guide.

Fixes #27533 specifically #27533 (comment) and #27533 (comment).

The outlined input should have a notch when displaying an empty value using the displayEmpty prop, even if the select isn't focused.

Before: https://codesandbox.io/p/sandbox/material-ui-outlined-select-label-is-not-rendering-properly-forked-8q5kwv?file=%2Fsrc%2FApp.js%3A25%2C18
After: https://codesandbox.io/p/sandbox/material-ui-outlined-select-label-is-not-rendering-properly-forked-q69vh7?file=%2Fpackage.json%3A12%2C34

[mui-bot]

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[michaldudak]

Thanks for the PR! The sandboxes you linked seem to be missing. Could you take a look?

[ZeeshanTamboli]

Thanks for the PR! The sandboxes you linked seem to be missing. Could you take a look?

Somehow it was set as private. I changed it to public now. Are you able to see it now? Looks like sandboxes will be private in future.

[michaldudak]

Yes, it's OK now, thanks!

Is the difference in margins related to your changes or are there different styles in these sandboxes?

[ZeeshanTamboli]

Is the difference in margins related to your changes or are there different styles in these sandboxes?

Not related to my changes. The CodeSandboxes had different styles. The "After" one had CssBaseline, hence the margin. I updated the link for the "After" CodeSandbox. You can check again.

[michaldudak]

The implementation looks fine to me. However, the before/after sandboxes still differ. Ideally, they should use the same sources and only reference different packages.

[ZeeshanTamboli]

However, the before/after sandboxes still differ. Ideally, they should use the same sources and only reference different packages.

Agreed. I've kept them the same now and referenced different packages. I updated the links in the description.