[core] Remove unnecessary conditional around .muiName =

[Janpot]

This was added in #42001. Why?

[mui-bot]

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[oliviertassinari]

It could be a use case for mui/pigment-css#84.

I have tried to apply this change with https://github.com/mui/material-ui/tree/4bcf32bbb8db43c5fe8c52d300116af00aae40d1/examples/material-ui-pigment-css-vite-ts (and found #44074 along the way), it seems to work fine. A big 💯 to move in this direction. If this code branche is needed, then muiName isn't applied, then it's broken, so in any cases, we can't have this code branch.

[Janpot]

Yep, also found that adding .displayName to a styled component breaks pigment. Still investigating.

[mnajdova]

I can confirm that it was added during the migration of Pigment CSS, because otherwise it breaks Pigment CSS. @brijeshb42 can likely share more info on why (or @siriwatknp as he was mainly driving the migration).

[brijeshb42]

It is fine to remove now since we added a fix in the Pigment transform itself.

[Janpot]

It is fine to remove now since we added a fix in the Pigment transform itself.

Does the fix apply to .displayName as well? It seems to break pigment in #44067

[brijeshb42]

On inspecting the code, I see that we only handle muiName and propTypes. We'll also need to add check for displayName.

[Janpot]

There is also defaultProps, and Toolpad is also attaching a static (Symbol) property to the component. I've seen other tools rely on similar patterns. Would it be possible to support just any static property on a component?