duplicated projects in landscape.yml

Hi,
I am doing some research for the CN AI WG and was processing the landscape.yml list. Not sure if this is ok, but found a few projects that are listed more than once. I can envision that happening, but given the the first one I checked (Apache Spark), it is unclear if its right.

```
% curl -s https://raw.githubusercontent.com/cncf/landscape/refs/heads/master/landscape.yml | yq -p yaml -o json | jq '.landscape[].subcategories[].items[].name' | sort | uniq -c | sort -n
... (all above here are listed 1 time)
1 "youki"
1 "zot"
2 "Alluxio"
2 "Apache Spark"
2 "Cassandra"
2 "ClickHouse"
2 "DeepFlow"
2 "Grafana"
2 "Kafka"
2 "Numaflow"
2 "Okahu"
2 "OpenLIT"
2 "OpenLLMetry"
2 "Permify"
2 "Presto"
2 "Prometheus"
2 "Pulsar"
2 "Redis"
2 "SpiceDB"
2 "Upbound (member)"
2 "Weaviate"
```

Just to on Apache Spark, it is listed as subcategories:

* Streaming & Messaging
* Data Architecture

I would not list Spark as streaming and messaging. Sure it streams things, but thats not the point of it. I think Data Architecture is fine.

Not to nit pick one entry, is there a rule about being listed more than once?

Start with landscape.yml and inspect the listed duplicate projects, including Apache Spark's Streaming & Messaging and Data Architecture entries. Compare the duplicate placements and determine whether the project data follows an established rule; done means the duplicate-handling rule and any needed landscape.yml corrections are clearly identified.

Written by the indexing model from the issue text.