RemoveItems converts empty maps and lists ({} and []) instead to null

[pjiang-dev]

I'm experiencing a similar issue as #302 except for RemoveItems()

For example in my CronJob jobTempalte i end up with a metadata: null which is not a nullable field

  "spec": {
    "concurrencyPolicy": "Allow",
    "failedJobsHistoryLimit": 1,
    "jobTemplate": {
      "metadata": null,

We should do the same as Extract items and preserve empty list/maps

# Starting value
mapOfMaps:
  b:
    a: "x"
    c: "z"

# Call RemoveItems to remove all nested fields
RemoveItems(mapOfMaps.b.a, mapOfMaps.b.c)

# BUG: Returns null
mapOfMaps:
  b: null

In my case the list/map is not empty before calling RemoveItems(). Only after calling RemoveItems() then the list/map is empty and returns null.

I think the correct behavior is we preserve the list or map if it becomes empty after using RemoveItems