Unnecessary nested arrays

[lukas-vlcek]

Example output of the plugin can be found here: https://github.com/opensearch-project/OpenSearch/issues/5481#issuecomment-1370369505

Notice that every array is nested in another array. For instance:

{
    "charFilters" : [
      [
        "html_strip",
        "mapping",
        "pattern_replace"
      ]
    ],
    "hunspellDictionaries" : [
      [ ]
    ]
}

That is a bug 🐛 🐞 !