Table - CSV export to Excel encoding issue

**What happened**: Special charaters are not converted correctly. Having a table with transformed headlines (maybe also without) containing special characters (like the german äöü) are not converted correctly. Opening the CSV with Excel (exported with Excel dialect) show strange signs instead of the correct special chars. **What you expected to happen**: Correctly encoded chars. **How to reproduce it (as minimally and precisely as possible)**: Look at the problem description. **Anything else we need to know?**: **Environment**: - Grafana version: 7.5.1 - Data source type & version: SimpleJSON - OS Grafana is installed on: Windows 2016 Server - User OS & Browser: Wundows/Macos Chrome - Grafana plugins: - Others: