Multi Select - Remove 'x' from selected values by default

[crutch12]

It's strange that selected disabled options still have the 'x' icon next to preview of an selected item

Here is how to hide that icon on your own: https://react-select.com/home#fixed-options

But I think we should hide them by default if an item is disabled (using state.isDisabled in multiValueRemove style function)

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Related to: #1503