Editable Select Field

[cqliu1]

Can you make an editable select field? Essentially it'd be an input field with a dropdown menu. We want to use it for number inputs with preset values like font size and rows per page for our table element.

[cjcenizal]

We could probably adapt EuiComboBox for this. For example, we could use the single selection example, but render the selected value as editable input instead of as a pill.

[chandlerprall]

I wonder what additional (if any) validation needs should be included? Maybe take advantage of the pattern attribute on input fields to limit the allowed characters, but that may not work well outside the digit-only use case.

[cchaos]

This was fixed in #1139 via singleSelection.asPlainText: bool