[BUG] QAT specific settings should only applicable for QAT codecs only.

What is the bug?

In the current implementation, the index.codec.qatmode is introduced but it does not validate if the setting can be applied to all codecs or not. Ideally, this setting should be applied only for QAT codecs.

How can one reproduce the bug?

Request:

curl --location --request PUT 'http://localhost:9200/index-10045' \
--header 'Content-Type: application/json' \
--data-raw '{
  "settings": {
    "index": {
      "codec": "zstd",
      "codec.qatmode": "auto"
    }
  }
}'

Response:

{
    "acknowledged": true,
    "shards_acknowledged": true,
    "index": "index-10045"
}

What is the expected behavior?

QAT specific settings should only be applied for QAT codecs

Start in src/main/java/org/opensearch/index/codec/customcodecs/Lucene99QatCodec.java at the index.codec.qatmode setting, then reproduce the issue with the provided curl request using the zstd codec. Trace how codec settings are validated and make the QAT-specific setting apply only to QAT codecs; done means the non-QAT case no longer accepts or applies it.