fix(date-textbox, calendar): clear behavior with ranges

[LuLaValva]

• Fixes ebay-date-textbox: the clear function isn’t working with range: true on the dateTo field, even when passing a null value or an empty string. #2295

Description

• Allow clearing date textbox with range
• Updated example to work with the changes. This makes the example more complicated, it may even be better to keep the simpler version even though it doesn't work when you toggle range to true.
• This uncovered a bug in ebay-calendar with clearing of dates, which I fixed

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🦋 Changeset detected

Latest commit: a59e3de

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@ebay/ebayui-core	Patch

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[LuLaValva]

This makes the example a little complicated, what do you think about leaving as-is and adding a comment instead that says this naive implementation won't work with range?

[agliga]

Hmm, what makes them complicated. Not sure I follow

[LuLaValva]

It just makes the example a little longer since it has to handle both cases. There will realistically never be an app that needs to handle both range and single select in the same spot.