Serialization of non-string-keyed dictionaries for untyped tables fails

[sl-at-ibm]

TL;DR = for untyped tables, dictionary column do not become [[k1,v1],[k2,v2],...] in payload. Rather, some object form is emitted, which causes an API error because of the (somehow) stringified keys.

Details: slack:

var row = new Row()
    {
      {
        "map_column_int_str",
        new Dictionary<int, string> { { 1, "value1" }, { 2, "value2" } }
      },
      {
        "map_column_strs1",
        new Dictionary<string, string>
        {
          { "key1", "value1" },
          { "key2", "value2" },
        }
      },
      { "title", "Once in a Living Memory" },
      { "author", "Kayla McMaster" },
    };