feat(datetime): add clear button to picker

[NiklasMerz]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

The datetime component is missing a button to clear the value

Issue Number: #17482

What is the new behavior?

I hacked a new button in the picker, to see how complex this changed is. Looks like this can easily be done with a new button on the default picker.

I am not sure about the tests. Please let me know if and how to add tests for this new feature.

Does this introduce a breaking change?

• Yes
• No

Other information

[liamdebeasi]

Thanks for the PR! We appreciate the contribution to Ionic Framework. We are currently working on a complete overhaul of ion-datetime as part of the next major version of Ionic Framework. One of the things you will be able to do in the updated component is provide custom buttons, including custom clear buttons.

Adding this feature now would cause additional breaking changes when we release the updated ion-datetime and we are trying to keep the breaking changes to a minimum. As a result, we are unable to accept this PR.

As we get closer to the launch of the next major version of Ionic Framework we will have a public beta, so there will be an opportunity to test this feature and provide feedback. Thank you!