Epic: Angular Cleanup - Frontend Group

**Why?** By Grafana 12 we have removed Angular from the core. There are though still some cleanup left to do to completely get rid of dead code intertwined in different areas of the codebase. This issue is to help different groups in Grafana track those areas and help them getting rid of this tech debt. - [ ] Grafana [devenv example dashboards](https://github.com/grafana/grafana/tree/main/devenv/dev-dashboards) should be updated to not use angular anymore (dashboards, dataviz) - [ ] Dashboards: Clean up [AutoRefreshIntervals](https://github.com/grafana/grafana/blob/main/public/app/features/dashboard/components/DashboardSettings/AutoRefreshIntervals.test.tsx) tests - [ ] Dashboards: [OptionsPaneOptions](https://github.com/grafana/grafana/blob/main/public/app/features/dashboard/components/PanelEditor/OptionsPaneOptions.tsx) has angular related styles - [ ] Dashboards: [PanelHeaderTitleItems](https://github.com/grafana/grafana/blob/main/public/app/features/dashboard/dashgrid/PanelHeader/PanelHeaderTitleItems.tsx) has angular related code - [ ] Dashboards: [variables/utils.ts](https://github.com/grafana/grafana/blob/main/public/app/features/dashboard-scene/variables/utils.ts#L204) has angular related code - [ ] Frontend Platform: Figure out what to do with [reducers](https://github.com/grafana/grafana/blob/main/public/app/features/datasources/state/reducers.ts#L45-L46) that couldn't use createSlice because of ImmerJs and angular mutating state - [ ] Frontend Platform: [navigation/patch directory](https://github.com/grafana/grafana/tree/main/public/app/core/navigation/patch) is all about angular - [ ] Frontend Platform: e2e tests have [isAngularPanel helper](https://github.com/grafana/grafana/blob/main/e2e/old-arch/utils/flows/openPanelMenuItem.ts#L13) [2](https://github.com/grafana/grafana/blob/main/e2e/utils/flows/openPanelMenuItem.ts#L12) - [ ] Frontend Platform: grafana/ui - [ModalsContext](https://github.com/grafana/grafana/blob/main/packages/grafana-ui/src/componen…