[ic-date-input] Improve deletion of full date via keyboard

[mi6-577]

Summary

User should be able to delete an entered value from the dateinput field via the keyboard as easily as they were able to enter the date initially.

💬 Description

This was raised as a result of Usability Testing of canary components. Participants didn't notice the clear 'X' icon to the right of the field and were attempting to use the Delete key to clear the entered date. In some cases, the user was attempting to double-click on the field to select all and then delete. Currently, delete button will only delete the current section of the date (e.g. Year) and the user would need to use the back arrow key on the keyboard to navigate to month.

💰 User value

This would help ensure that functionality of the dateinput field matches the user's mental model of how it should behave.