[LogsDB] [Stack 8.19.20-SNAPSHOT] [mongodb] Failing test daily: system test: collstats in mongodb.collstats

- Stack version: 8.19.20-SNAPSHOT
- LogsDB: enabled
- Package: mongodb
- Failing test: system test: collstats
- DataStream: collstats
- Owners:
- @elastic/obs-infraobs-integrations

Failure:
```
test case failed: one or more errors found in documents stored in metrics-mongodb.collstats-31558 data stream: [0] field "mongodb.collstats.stats.capped" is undefined
[1] field "mongodb.collstats.stats.freeStorageSize" is undefined
[2] field "mongodb.collstats.stats.scaleFactor" is undefined
```

First build failed: https://buildkite.com/elastic/integrations/builds/47076

Latest 5 failed builds:
- https://buildkite.com/elastic/integrations/builds/48320
- https://buildkite.com/elastic/integrations/builds/48399
- https://buildkite.com/elastic/integrations/builds/48456
- https://buildkite.com/elastic/integrations/builds/48531
- https://buildkite.com/elastic/integrations/builds/48613

Start by running the mongodb `collstats` system test for the LogsDB-enabled 8.19.20-SNAPSHOT integration and inspect the documents in the `metrics-mongodb.collstats` data stream. Trace the collection statistics fields reported as undefined, then verify that the test passes with `capped`, `freeStorageSize`, and `scaleFactor` present.

Written by the indexing model from the issue text.