fix: read-only css for input

[manthan-jsharma]

Fixes #3192

Technical details

This PR contains the changes where two things are done

1. addition of read-only class only if readonly prop is passed from parent
2. making read-only selector to class as read-only class can be used as conditional render

Screenshots

Screenshots of input with read only prop

Screenshots of input inside ul element without read only prop

Screenshots of normal input

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[manthan-jsharma]

@pavish, could you kindly review this PR? I've thoroughly examined the codebase and found that this is the only instance where 'ul' is wrapped inside a custom input.

[seancolsen]

Note we have two PRs for the same issue: #3197 and #3196. @pavish I'll leave it to you as to how to best handle this.

[pavish]

@manthan-jsharma Thanks for the PR!

The approach you've taken is mostly good, I have a tiny comment: You exports readOnly as a prop, which isn't required since readonly is an html attribute and we would like to use in a similar manner which is already handled by $$restProps.

I've added a small commit 94733c5 which removes this external export.