Interpolation: Backwards compatibility for SafeSerializableSceneObject

[dprokop]

When using latest scenes apps against an older version of grafana (prior https://github.com/grafana/grafana/pull/90272), the sceneGraph.interpolate will get a SafeSerializableSceneObject as a target which... isn't a scene object but a wrapper for one. This is because we are passing plain scopedVars.__sceneObject.value here https://github.com/grafana/grafana/blob/v11.1.0/public/app/features/templating/template_srv.ts#L253 which used to be a plain scene object, but it isn't anymore

📦 Published PR as canary version: 5.6.2--canary.843.10055590290.0

:sparkles: Test out this PR locally via: ```bash npm install @grafana/scenes-react@5.6.2--canary.843.10055590290.0 npm install @grafana/scenes@5.6.2--canary.843.10055590290.0 # or yarn add @grafana/scenes-react@5.6.2--canary.843.10055590290.0 yarn add @grafana/scenes@5.6.2--canary.843.10055590290.0 ```

[ivanortegaalba]

This is not needed anymore. Closing after checking with @dprokop