feat: add disabled attribute when readonly property is true

[scouser03]

No description provided.

[marttinnotta]

Hi and thank you for your contribution!

Readonly and disabled property have different purposes and should not be mixed like that. While readonly prevents user from editing the field disabled state will in some browser remove event listeners entirely from input.

I suggest to change your code so that instead of disabled state use readonly state instead and don't allow toggling picker when it's in readonly mode.