Bug: invalid unicode characters caused UnicodeEncodeError

[shaunahu]

As discussed in this comment, there are a few global attributes contains invalid unicode characters, which can lead to UnicodeEncodeError when converting Zarr to NetCDF. They are:

dataset	global attribute	invalid characters
radar_CoffsHarbour_wind_delayed_qc	file_version_quality_control	\udcc2\udca0
satellite_ghrsst_l4_ramssa_1day_multi_sensor_australia	acknowledgement	\udce2\udc80\udc93
satellite_ghrsst_l4_gamssa_1day_multi_sensor_world	acknowledgement	\udce2\udc80\udc93