geomap: Update dashboard variable with view data part deux

<!-- Please only use this template for submitting feature requests --> **Why is this needed**: It is handy to have a dashboard that has a geomap with measurementpoints and a timeseries panel next to it that only shows the measurementpoints that are visible on the geomap. Currently it is not possible to filter a panel easily by location. **What would you like to be added**: It seems to me this feature has been requested before. there is even a pull request for it. https://github.com/grafana/grafana/pull/97173 Can you investigate this pull request, perhaps reconsider merging it ? **Who is this feature for?** any user that has sensors / measurementpoints that are bound to areas (IOT etc.)