fix(android): reopen picker when design changes

[giaBaoJS]

Summary

On Android, switching the design prop on a mounted picker closes the dialog and never reopens it.

RNDateTimePickerAndroid has two effects. The first one dismisses the dialog and lists design in its dependencies, because the default and Material pickers are backed by different native modules:

https://github.com/react-native-datetimepicker/datetimepicker/blob/a523007/src/datetimepicker.android.js#L44-L48

The second one opens the dialog, forwards design in its params, but does not list it in its dependencies:

https://github.com/react-native-datetimepicker/datetimepicker/blob/a523007/src/datetimepicker.android.js#L84-L91

So when design changes, React runs the first effect's cleanup, which calls DateTimePickerAndroid.dismiss(mode, previousDesign), and the second effect never re-runs. The picker disappears. mode is already handled the same way and works correctly; design was simply missed when the Material pickers were added in #952.

The fix adds design to the second dependency array, so a design change tears down the old dialog and opens the new one, exactly like a mode change.

Test Plan

Added a Jest test that renders the Android component with design="default", rerenders it with design="material", and asserts DateTimePickerAndroid.open is called for both designs.

On master the test fails, showing only the first open call:

    - Expected  - 1
    + Received  + 0

      Array [
        "default",
    -   "material",
      ]

With the fix, yarn test is green (25 tests) and yarn lint reports 0 errors, same warning count as master.

What's required for testing (prerequisites)?

yarn

What are the steps to reproduce (after prerequisites)?

yarn test

Compatibility

OS	Implemented
iOS	❌
Android	✅

Checklist

• I have tested this on a device and a simulator
• I added the documentation in README.md
• I updated the typed files (TS and Flow)
• I added a sample use of the API in the example project (example/App.js)
• I have added automated tests, either in JS or e2e tests, as applicable