2726 - IdsDataGrid dropdown editor async beforecelledit

[jdilag90]

Explain the details for making this change. What existing problem does the pull request solve?
Users can now pass an async function or Promise to the vetoable beforecelledit event's response callback.
This allows user to perform aync operations like database fetches before vetoing beforecelledit event.

Related github/jira issue (required):
Closes #2726

Steps necessary to review your pull request (required):

1. Checkout branch
2. Go to http://localhost:4300/ids-data-grid/beforecelledit-async.html
3. Test bookCurrency column dropdowns and make sure dropdown options load properly
4. Test http://localhost:4300/ids-data-grid/editable.html for any regressions

Included in this Pull Request:

• Some documentation for the feature.
• A test for the bug or feature.
• A note to the change log.

[glenlieorillo]

Screen.Recording.2024-09-09.at.5.22.41.PM.mov