[Backport Fixes #12828] New remote datasets are not registered inside…

[mattiagiupponi]

… proxy allowed hosts when GeoNode runs asynchoronously

Checklist

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[mattiagiupponi]

Importer PR GeoNode/geonode-importer#282

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 61.46%. Comparing base (de98ae6) to head (443fc32).
Report is 15 commits behind head on 4.4.x.

Additional details and impacted files

@@            Coverage Diff             @@
##            4.4.x   #12852      +/-   ##
==========================================
- Coverage   64.14%   61.46%   -2.68%     
==========================================
  Files         890      890              
  Lines       53774    53782       +8     
  Branches     6629     6630       +1     
==========================================
- Hits        34492    33059    -1433     
- Misses      17766    19242    +1476     
+ Partials     1516     1481      -35     

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