[Chip] Fix error when theme value is a CSS variable

[siriwatknp]

Before: https://codesandbox.io/s/joy-ui-feat-material-ui-forked-cw0rw5?file=/demo.tsx

Problem

Chip throws an error if you have custom theme value that is a CSS variable:

const theme = extendTheme({
  colorSchemes: {
    light: {
      palette: {
        text: {
          primary: 'var(--mui-palette-grey-900)',
          primaryChannel: '12 12 12',
        },
      },
    },
  },
});

<CssVarsProvider theme={theme}>
  <Chip label="chip" />
</CssVarsProvider>

This is because the calculation of deleteIconColor with alpha() is done before checking theme.vars.

---

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[mui-bot]

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[mj12albert]

Looks good !