[@mantine/core] MultiSelect: inject index to ValueCopmonent

[vaynevayne]

inject index to ValueComponent

[vaynevayne]

to support maxTagCount, like https://ant.design/components/select-cn#components-select-demo-responsive
we need inject index to ValueComponent,

You might want to use value.length simulation, but it's not.
User cannot implement it. because value.length control only one ValueCopmponent ,
we need render different value,so we need index
https://codesandbox.io/s/loving-chihiro-tmchzu?file=/src/Demo.tsx

[rtivital]

Thanks!