Change the ingest simulate api to not include dropped documents (#44161)
If documents are dropped by the `drop` processor then
these documents are returned as a `null` value in the response.
=== Example
Create pipeline:
```
PUT _ingest/pipeline/droppipeline
{
"processors": [
{
"set": {
"field": "bla",
"value": "val"
}
},
{
"drop": {}
}
]
}
```
Simulate request:
POST _ingest/pipeline/droppipeline/_simulate
{
"docs": [
{
"_source": {
"message": "text"
}
}
]
}
Response:
```
{
"docs": [
null
]
}
```
Response if verbose is enabled:
```
{
"docs": [
{
"processor_results": [
{
"doc": {
"_index": "_index",
"_type": "_doc",
"_id": "_id",
"_source": {
"message": "text",
"bla": "val"
},
"_ingest": {
"timestamp": "2019-07-10T11:07:10.758315Z"
}
}
},
null
]
}
]
}
```
Closes #36150
* Abort pipeline simulation in verbose mode when document has been dropped
by drop processor
e066133016