AdHoc filters: Allow adding custom value while loading

[ashharrison90]

• adds the allowCreateWhileLoading option to the value select
• adjusts when isValuesOpen is set to true to be as soon as the onClick is fired. otherwise the menu will reopen once the options finally resolve even if you've already selected and added a custom value

Fixes https://github.com/grafana/hyperion-planning/issues/23

📦 Published PR as canary version: 4.14.2--canary.721.8986239090.0

:sparkles: Test out this PR locally via: ```bash npm install @grafana/scenes@4.14.2--canary.721.8986239090.0 # or yarn add @grafana/scenes@4.14.2--canary.721.8986239090.0 ```

[grafanabot]

:rocket: PR was released in v4.14.2 :rocket: