Possibility to refresh variable options based on state changes

[mdvictor]

Add possibility to manually trigger a variable options refresh after a state change. Needed for various variable components in react scenes. E.g.: https://github.com/grafana/scenes/pull/818

📦 Published PR as canary version: 5.7.5--canary.827.10385100405.0

:sparkles: Test out this PR locally via: ```bash npm install @grafana/scenes-react@5.7.5--canary.827.10385100405.0 npm install @grafana/scenes@5.7.5--canary.827.10385100405.0 # or yarn add @grafana/scenes-react@5.7.5--canary.827.10385100405.0 yarn add @grafana/scenes@5.7.5--canary.827.10385100405.0 ```

[grafanabot]

:rocket: PR was released in v5.7.5 :rocket: