[dataformats][templates][panels][editor] Fix the data loaded

The python ordered dictionary was shown raw, use the
string version of the declaration to feed the editor.
1 job for fix_dataformat_declaration_preview in 15 minutes and 41 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #210356
docker-build
build_linux_36

00:15:41

69.0%