#1423: DatePicker should have clearable option (closes #1423)

[marcopiii]

Closes #2520628

⚠️ The line above was added during the automatic migration of all github project issues to Kaiten. The old GH issue link is kept here for reference (it is now deprecated, continue follow the original issue on Kaiten).

Closes #1423

Test Plan

tests performed

if isClearable={false} or not defined

• value has to be defined and it can't be null
• if defined, onChange has to be (date: LocalDate) => void
• there is no clear icon

if isClearable={true}

• value has to be defined, but can be null
• if defined, onChange has to be (date: LocalDate | null) => void

• there is a clear icon

⚠️ this is a breaking change since the component was clearable by default and value was optional, now it's not clearable by default and value is always mandatory

[marcopiii]

@veej I applied the requested changes 👍 test plan has been updated

[kanbanbot]