[EuiSuperDatePicker] Fix duplicate value when pasting absolute value

[mgadewoll]

Summary

Related Kibana issue: elastic/kibana#205633

This PR fixes an issue on EuiSuperDatePicker where pasting a date would sometimes result in the date being appended instead of being replaced.
The issue was that the onPaste event would trigger the onChange event on the EuiFieldText input which clashed with the controlled value update. This seemed to be a race condition as depending on application this resulted either in a duplicated value or not, depending on which state was updated first.

This behavior is not reproducible on EUI (neither docs not Storybook), but it can be observed by checking the value of the internally used EuiFieldText which showed the duplication.

The solution is to preventDefault on onPaste and just let the controlled value update the input.

before

Screen.Recording.2025-02-07.at.10.40.18.mov

after

Screen.Recording.2025-02-07.at.10.36.00.mov

QA

• the updated unit test passes
  • (optional) comment out the added event.preventDefault and manually run the test locally (the test should fail)
• manually verify non-duplicated input value:
  • checkout this PR
  • comment out the update adding event.preventDefault on the onPaste event
  • console log the event.target.value on the onChange event of the EuiFieldText
    • the onChange event is not triggered on pasting
    • the input value updates correctly
    • validation for the date picker works correctly

EuiFieldText` value before the fix

Screen.Recording.2025-02-07.at.10.48.26.mov

EuiFieldText` value after the fix

Screen.Recording.2025-02-07.at.10.49.32.mov

General checklist

• Browser QA
  • Checked in both light and dark modes
  • Checked in mobile
  • Checked in Chrome, Safari, Edge, and Firefox
  • Checked for accessibility including keyboard-only and screenreader modes
• Docs site QA
  • Added documentation
  • Props have proper autodocs (using @default if default values are missing) and **[playground toggles](https://github.com/elastic/eui/blob/main/wiki/contributing-to-eui/documenting/playgrounds.md)**
  • Checked Code Sandbox works for any docs examples
• Code quality checklist
  • Added or updated jest and cypress tests
  • Updated visual regression tests
• Release checklist
  • A changelog entry exists and is marked appropriately.
  • If applicable, added the breaking change issue label (and filled out the breaking change checklist)
• Designer checklist
  • If applicable, file an issue to update EUI's Figma library with any corresponding UI changes. (This is an internal repo, if you are external to Elastic, ask a maintainer to submit this request)

[kibanamachine]

Preview staging links for this PR:

• Docs site: https://eui.elastic.co/pr_8311/
• Storybook: https://eui.elastic.co/pr_8311/storybook
• New docs: https://eui.elastic.co/pr_8311/new-docs

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: b5ea979

cc @mgadewoll

[acstll]

Awesome work 🙇