Content Picker search can run less often

[johnwatkins0]

Is your enhancement related to a problem? Please describe.
The search runs every time input changes. While this is generally not a problem, it can be an issue on slow connections, and it is technically possible to type so fast that you reach the limit of the simultaneous requests the browser will allow.

Describe the solution you'd like

No need to debounce. Instead, we can just make sure only one fetch request is running at a time. After a fetch completes, we check whether the search term has changed; if it has, search again. This way we will still make a lot of requests that are never surfaced in the UI as the user types, but it will be fewer requests than what the component does now.

Designs

Describe alternatives you've considered

Debouncing, though as described above, I don't think it's necessary.

Additional context

I'll send a PR for this, unless someone else sees this and wants to try it.

[xavortm]

Also probably fixed in #71

[fabiankaegy]

Closing this as it appears to be fixed as of #71