clear query button inconsistently displayed for search / EuiSearchBarProps

[jpcarey]

Using the EuiInMemoryTable with search / EuiSearchBarProps, the clear query button does not display when the search state is externally provided.

To reproduce:
The "In-memory table with search and external state" example displays this issue. Just click any of the left side selectable cards, and the query will be updated. Add a space in the search bar and submit, and the clear query button will appear.

[thompsongl]

A quick look before the issue was created showed that search_box uses defaultValue for query values, but field_search looks at value to determine whether to display the clear button. Just a little debug help for whoever takes this on.

[chandlerprall]

Another bug with the controlled input, reproducible on the Controlled docs:

If a pre-built value is selected and the input then changed by the user, that same pre-built value won't reselect. This is likely a bug in the example docs and not EUI src.