Double sorting with aggregation not working

Describe the bug

When we request collection with aggregation with sorting by two fields we see two bugs:

• Missing sorting
• Different results for each call

Steps to reproduce (if applicable)

1. Download dataset and index config from https://dev2.manticoresearch.com/index-settings-and-data.zip
2. Run Quickwit in Docker quickwit/quickwit:0.8.1
3. Create index (config provided in attached archive):

export HOST='http://localhost:7280'

curl -s -XPOST "${HOST}/api/v1/indexes" \
    --header "content-type: application/yaml" \
    --data-binary @./index-config.yaml

4. Upload data (Dataset is pretty big, so we split it into chunks):

split -l 10000 ./data.jsonl ./data_splitted.

echo "Starting loading"
for f in ./data_splitted.*; do
    echo "Upload chunk $f"
    curl -s -XPOST "${HOST}/api/v1/hn_small/ingest?commit=force" --data-binary @$f
    rm $f
done
echo "Finished"

5. Perform query:

curl --location '${HOST}/api/v1/hn_small/search' \
--header 'Content-Type: application/json' \
--data '{"query":"*","max_hits":0,"aggs":{"comment_ranking_avg":{"terms":{"field":"comment_ranking","size":20,"order":{"avg_field":"desc","_key":"desc"}},"aggs":{"avg_field":{"avg":{"field":"author_comment_count"}}}}}}'

6. We got results with the wrong sorting

{
    "num_hits": 1165439,
    "hits": [],
    "elapsed_time_micros": 6665,
    "errors": [],
    "aggregations": {
        "comment_ranking_avg": {
            "buckets": [
                {
                    "avg_field": {
                        "value": 3504.0
                    },
                    "doc_count": 1,
                    "key": 928.0 # Should be 2nd
                },
                {
                    "avg_field": {
                        "value": 3504.0
                    },
                    "doc_count": 1,
                    "key": 961.0 # Should be 1st
                },
                {
                    "avg_field": {
                        "value": 3504.0
                    },
                    "doc_count": 1,
                    "key": 730.0
                },
.....                

7. if you repeat the request several times it can return different results (for the same query)

{
    "num_hits": 1165439,
    "hits": [],
    "elapsed_time_micros": 9610,
    "errors": [],
    "aggregations": {
        "comment_ranking_avg": {
            "buckets": [
                {
                    "avg_field": {
                        "value": 64.0
                    },
                    "doc_count": 1,
                    "key": 1305.0
                },
                {
                    "avg_field": {
                        "value": 117.0
                    },
                    "doc_count": 1,
                    "key": 1296.0
                },
                {
                    "avg_field": {
                        "value": 40.0
                    },
                    "doc_count": 1,
                    "key": 1289.0
                },
                {
                    "avg_field": {
                        "value": 87.0
                    },
                    "doc_count": 1,
                    "key": 1287.0
                },
......

PS: Sometimes it returns results without grouping. In that case you should reindex your dataset

"buckets": [
                {
                    "avg_field": {
                        "value": 3504.0
                    },
                    "doc_count": 1,
                    "key": 961.0
                },
                {
                    "avg_field": {
                        "value": 3080.0
                    },
                    "doc_count": 1,
                    "key": 980.0
                },
                {
                    "avg_field": {
                        "value": 3077.0
                    },
                    "doc_count": 1,
                    "key": 1176.0
                },

So generally we can get 3 different results for one query.

PS: Elasticsearch compatible URL has the same behaviour

Expected behavior
It should return the dataset like provided below

{
    "num_hits": 1165439,
    "hits": [],
    "elapsed_time_micros": 6665,
    "errors": [],
    "aggregations": {
        "comment_ranking_avg": {
            "buckets": [
                {
                    "avg_field": {
                        "value": 3504.0
                    },
                    "doc_count": 1,
                    "key": 961.0
                },
                {
                    "avg_field": {
                        "value": 3504.0
                    },
                    "doc_count": 1,
                    "key":  928.0
                },
                {
                    "avg_field": {
                        "value": 3504.0
                    },
                    "doc_count": 1,
                    "key": 730.0
                },
..... 

Configuration:
Please provide:

1. Output of quickwit --version

Quickwit 0.8.1 (aarch64-unknown-linux-gnu 2024-03-29T14:09:41Z e6c5396)

2. The index_config.yaml

 Provided in the attached archive)