Parsing is incomplete when trailing object keys have null values

[TannerPerrien]

When ImportJSON retrieves an object with null value fields, it drops those keys in the resulting output.

Example 1: This drops fields
INPUT

{
  field1: "1",
  field2: "2",
  field3: null,
  field4: null,
}

OUTPUT

{
  field1: "1",
  field2: "2"
}

Example 2: This works ok

{
  field1: "1",
  field2: "2",
  field3: null,
  field4: null,
  field5: "5"
}

OUTPUT

{
  field1: "1",
  field2: "2",
  field3: null,
  field4: null,
  field5: "5"
}