[typescript] Replace Array API with ReadonlyArray about material-ui

[DiegoAndai]

This could be a good improvement to ship in v6, will add it to the milestone

[ant-plotnikov]

hey everyone. can I pick this up?

[oliviertassinari]

This could be a good improvement to ship in v6, will add it to the milestone

@DiegoAndai I wonder, I feel that major milestones should be focused on changes that require breaking changes (big features that require breaking changes or new major features to offset the removal of deprecated APIs) to decorelate things.
(e.g. I think it's closer to how MUI X operates for majors)

The rest could go into iteration plans like TypeScript has microsoft/TypeScript#56948 (3 months) or VS Code has microsoft/vscode#201255 (1 month).

This issue is small, we could add "good to take" and delegate to the community, optimizing for whenever a community member has time to donate (overall maximizing "time donation" for the community).

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It's also a Base UI issue.

[oliviertassinari]

We migrated a good chunk in #40754 and #40972 which is great but I think the issue should be about updating all our public APIs to accept read only arrays, there are more e.g.

material-ui/packages/mui-system/src/Unstable_Grid/GridProps.ts

Line 7 in 4a884da

type ResponsiveStyleValue<T> = T | Array<T | null> | { [key in Breakpoint]?: T | null };

material-ui/packages/mui-base/src/useAutocomplete/useAutocomplete.d.ts

Line 31 in 4a884da

? Array<Value | AutocompleteFreeSoloValueMapping<FreeSolo>>