title: Array of JSON in Athena is read incorrectly and can't be unnested
body: <p>I have column called <code>uf</code> that contains an array of JSON objects. Here is a mockup:</p>
  
  <pre><code>[
      {"type": "browserId", "name": "", "value": "unknown"},
      {"type": "campaign", "name": "", "value": "om_227dec0082a5"},
      {"type": "custom", "name": "2351350529", "value": "10148"},
      {"type": "custom", "name": "9501713387", "value": "true"},
      {"type": "custom", "name": "9517735577", "value": "true"},
      {"type": "custom", "name": "9507402548", "value": "true"},
      {"type": "custom", "name": "9733902068", "value": "true"}
  ]
  
  </code></pre>
  
  <p>I'm trying to get this as child records but for some reason I can't find the right way to unnest it first. Then I noticed that my whole array is wrapped into another JSON object..</p>
  
  <p>This is where I'm at:</p>
  
  <p>I tried simple select and noticed that the result is:</p>
  
  <pre><code>[{type=[{"type": "browserId", "name": "", "value": "ff"}, name=null, value=null}]
  </code></pre>
  
  <p>The definition for this column is as follows:</p>
  
  <pre><code>{
      "Name": "uf",
      "Type": "array&lt;struct&lt;type:string,name:string,value:string&gt;&gt;"
  }
  </code></pre>
  
  <p>Is the definition incorrect and that's why I get my whole array wrapped in another json array?</p>
  
  <p>-- edit
  Here is the example of my csv file (tab delimited). Spent last two days trying to see if it's something about JSON that makes Glue not recognise column as array of JSON but I created a new column with simple array of JSON that was correctly assigned as <code>array&lt;struct</code> but after querying I was getting exactly the same problem as above</p>
  
  <pre><code>timestamp   project_id  campaign_id experiment_id   variation_id    layer_holdback  audience_names  end_user_id uuid    session_id  snippet_revision    user_ip user_agent  user_engine user_engine_version referer global_holdback event_type  event_name  uf  active_views    event_features  event_metrics   event_uuid
  1570326511  74971132    11089500404 11097730080 11078120202 false   []  oeu1535997971348r0.4399811351004357     AUTO    6540    5.91.170.0  Mozilla/5.0 (Linux; Android 7.0; SAMSUNG SM-G925F Build/NRD90M) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/9.2 Chrome/67.0.3396.87 Mobile Safari/537.36  js  0.128.0 https://www.zavamed.com/uk/account/ false   view_activated  10832783364 [{"type": "browserId", "name": "", "value": "unknown"}, {"type": "device", "name": "", "value": "mobile"}, {"type": "device_type", "name": "", "value": "phone"}, {"type": "referrer", "name": "", "value": "https:\/\/www.google.co.uk\/"}, {"type": "source_type", "name": "", "value": "campaign"}, {"type": "currentTimestamp", "name": "", "value": "-1631518596"}, {"type": "offset", "name": "", "value": "-60"}]    []  []  []  4926a5f1-bbb5-4553-9d0b-b26f773fa0f4
  
  </code></pre>