SceneQueryRunner: Do not set panelId by default

[torkelo]

Fixes https://github.com/grafana/scenes/issues/739

Graphite has this old condition

  if (options.panelId) {
      httpOptions.requestId = this.name + '.panelId.' + options.panelId;
   }

which is causing duplicate requestId (and hence cancelled requests).

Think it should be fine to leave this undefined (it's optional in the type at least)

📦 Published PR as canary version: 4.27.0--canary.776.9400928706.0

:sparkles: Test out this PR locally via: ```bash npm install @grafana/scenes-react@4.27.0--canary.776.9400928706.0 npm install @grafana/scenes@4.27.0--canary.776.9400928706.0 # or yarn add @grafana/scenes-react@4.27.0--canary.776.9400928706.0 yarn add @grafana/scenes@4.27.0--canary.776.9400928706.0 ```

[grafanabot]

:rocket: PR was released in v4.28.0 :rocket: